Remote Sensing Techniques for Oceanography Satelitte and In Situ Observations


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Remote Sensing Techniques for Oceanography Satelitte and In Situ Observations

  1. 1. Remote Sensing Techniques for Hydrosphere Arife Tuğsan ISIACIK COLAKIstanbul Technical University Faculty of Maritime, Tuzla 34940, Turkey
  2. 2. AGENDA1. Definition of Earth Science-Hydrology-Oceanography2. Why do WE study the oceans?3. Remote Sensing Study Area Hydrology - Oceans & Coastal Monitoring4. Critical Marine Issues5. Ocean and Water Parameters -Ocean Monitoring and Forecasting- Technical Information for Instruments and In-Situ Observations Systems6. RS Application Examples for the Critical Marine Issues7. Conclusion
  3. 3. 1.What is Earth Science? Earth science is a broad term for any branch of science that deals with the study of any part of the Earth, including its environments, climates, and composition. There are several general types of earthscience that are roughly grouped according to the broader fields into which they fall and which correspond to four area that divide the Earth and its immediate environment:1. the atmosphere,2. the lithosphere or geosphere,3. the biosphere, and4. the hydrosphere are the domains into which all types of Earth science fall
  4. 4. What is Hydrosphere andHyrdology? The hydrosphere in physical geography describes the combined mass of water found on, under, and over the surface of a planet. Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage basin management and water quality, where water plays the central role. Oceanography and meteorology are not included because water is only one of many important aspects within those fields.
  5. 5. Earth Hydrosphere The Earths hydrosphere consists chiefly of the oceans, but technically includes all water surfaces in the world, including inland seas, lakes, rivers, and underground waters down to a depth of 2,000 m. Approximately 71% of the planets surface (~3.6x108 km2) is covered by saline water that is customarily divided into several principal oceans and smaller seas.
  6. 6. Branches Chemical hydrology is the study of the chemical characteristics of water. Ecohydrology is the study of interactions between organisms and the hydrologic cycle. Hydrogeology is the study of the presence and movement of ground water. Hydroinformatics is the adaptation of information technology to hydrology and water resources applications. Hydrometeorology is the study of the transfer of water and energy between land and water body surfaces and the lower atmosphere. Isotope hydrology is the study of the isotopic signatures of water. Surface hydrology is the study of hydrologic processes that operate at or near Earths surface. Drainage basin management covers water-storage, in the form of reservoirs, and flood-protection. Water quality includes the chemistry of water in rivers and lakes, both of pollutants and natural solutes.
  7. 7. Applications of Hydrology Determining the water balance of a region. Determining the agricultural water balance. Designing riparian restoration projects. Mitigating and predicting flood, landslide and drought risk. Real-time flood forecasting and flood warning. Designing irrigation schemes and managing agricultural productivity. Part of the hazard module in catastrophe modeling. Providing drinking water. Designing dams for water supply or hydroelectric power generation. Designing bridges. Designing sewers and urban drainage system. Analyzing the impacts of antecedent moisture on sanitary sewer systems. Predicting geomorphological changes, such as erosion or sedimentation. Assessing the impacts of natural and anthropogenic environmental change on water resources. Assessing contaminant transport risk and establishing environmental policy guidelines.
  8. 8. HYDROSPHERE The hydrosphere encompasses water in all three phases (i.e., ice, liquid, and vapor) that continually cycles from one reservoir to another witin the Earth system. Water is unique among the chemical components of the Earth system in that it is the only naturally occurring substance that co-exists in all three phases at normal temperatures and pressures near Earth’s surface.
  9. 9. The ocean, by far the largest reservoir of waterin the hydrosphere, covers about 70.8% of the planet’sAbout 97.2% of the hydrosphere is ocean salt water; otherAfter the oceans next largest reservoir in the hydrosphereis glacial ice, most of which covers much of Antarctica andGreenland. Ice and snow make up 2.1% of water in thehydrosphere Planet Earth,
  10. 10. Oceanography Oceanography also called oceanology or marine science, is the branch of Earth science that studies the ocean. It covers a wide range of topics, including marineorganisms and ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries.
  11. 11. The study of oceanography is divided into branches: Biological oceanography, or marine biology, is the study of the plants, animals and microbes of the oceans and their ecological interaction with the ocean; Chemical oceanography, or marine chemistry, is the study of the chemistry of the ocean and its chemical interaction with the atmosphere; Geological oceanography, or marine geology, is the study of the geology of the ocean floor including plate tectonics and paleoceanography; Physical oceanography, or marine physics, studies the oceans physical attributes including temperature-salinity structure, mixing, waves, internal waves, surface tides,internal tides, and currents.
  12. 12. 2. WHY DO WE STUDY THE OCEANS?We have to study oceans ; to develop an understanding of the total Earth system and the effects of natural and human-induced changes on the global environment. Our oceans play a major role in influencing changes in the worlds climate and weather. Collecting and analyzing long-term ocean data is very important source. The analysis of remotely-sensed ocean data makes it possible to understand the ocean in new and exciting ways.
  13. 13. … Using remote sensing data and computer models, it is possible investigate how the oceans affect the evolution of weather, hurricanes, and climate. Oceans control the Earths weather as they heat and cool, humidify and dry the air and control wind speed and direction.
  14. 14. … Long-term weather patterns influence water supply, food supply, trade shipments, and property values. We cant escape the weather, or even change it--but being able to predict its impact. And only by understanding the dynamics of the oceans can we begin to do this.
  15. 15. 3. Remote Sensing Study AreaHydrology - Oceans & CoastalMonitoring
  16. 16. RS Hydrological Applicationsinclude : 1. wetlands mapping and monitoring, 2. soil moisture estimation, 3. snow pack monitoring / delineation of extent, 4. measuring snow thickness, 5. determining snow-water equivalent, 6. river and lake ice monitoring, 7. flood mapping and monitoring, 8. glacier dynamics monitoring (surges, ablation) 9. river /delta change detection 10. drainage basin mapping and watershed modelling
  17. 17. RS;Oceans & Coastal Monitoring Applications Ocean pattern identification:  currents,  regional circulation patterns,  shears,  frontal zones,  internal waves, gravity waves,  eddies, upwelling zones,  shallow, water bathymetry
  18. 18.  Storm forecasting wind and wave retrieval Fish stock and marine mammal assessment water temperature monitoring water quality ocean productivity, phytoplankton concentration and drift aquaculture inventory and monitoring oil spill mapping and predicting oil spill extent and drift strategic support for oil spill emergency response decisions Shipping, navigation routing, traffic density studies operational fisheries surveillance near-shore bathymetry mapping Intertidal zone, tidal and storm effects delineation of the land /water interface mapping shoreline features / beach dynamics coastal vegetation mapping
  19. 19. 4. Critical Marine Issues  Maritme Safety And Security  Marine Resources  Coastal & Marıne Envıronment  Weather, Clımate & Seasonal Forecastıng  Overfishing  Sea Temoerature Rise  Marine Pollution  Sea Level Rise  Marine Invasive Species
  20. 20. 5. OCEAN MONITORINGand FORECASTING For OCEAN MONITORING and FORECASTING we have to know ocean parameters for the critical marine issues first of all.
  21. 21. OCEAN PARAMETERS Temperature Currents Salinity Sea ice Sea level Wind Biogeochemistry Water Quality Parameters
  22. 22. Why measure sea surfacetemperature?  Sea surface temperature (SST) is the temperature of the ocean near the surface. Knowing the temperature of this part of the ocean is absolutely essential for many reasons. For oceanographers, meteorologists and climatologists, it is one of the signs/results of the exchange of energy between the ocean and the atmosphere. For marine biologists, it is the parameter that determines the development of different biological organisms. For fishermen, important temperature variations as seen on a map (thermal fronts) indicate prolific fishing zones.  Meteorological phenomena such as El Niño or tropical hurricanes/cyclones are the direct consequences of specific temperature variations at the sea-surface.  Sea surface temperature varies between -1,8°C, temperature at which sea water freezes, and +30°C near/below the Equator.
  23. 23. How SST is measured By satellite •Infrared radiometers •Microwave radiometers In-situ techniques •Ships of opportunity •Drifting buoys •Argo profiling floats •Moored buoys Numerical models Numerical atmospheric or oceanic models are also capable of calculating sea surface temperature. Models are calibrated by comparing the sea surface temperature produced by the model with that measured by different sensors.
  24. 24. Satellite InstrumentsInstrument Type Ocean Parameter Instrument Name Satellite UsedSpectroradiometer Sea Surface MODIS Aqua (NASA, USA) Temperature MERIS Envisat (ESA, Europe)Infrared Sea Surface AVHRR (NOAA, USA) +radiometer Temperature AATSR METOP (Eumetsat, MODIS Europe) Envisat (ESA, Europe) SEVIRI Aqua, Terra (NASA, GOES USA) MeteoSat ( Eumetsat, Europe) (NOAA, USA) DMSP (NASA, USA)Microwave Sea Surface SSM/ITMI DMSP (NASA, USA)radiometer Temperature AMSR-E TRMM (NASA, USA) MWR Aqua (NASA, USA) + JMR, AMR (developed by JAXA,
  25. 25. Which Satellite Instruments areused for monitoring SST ? MODIS (or Moderate Resolution Imaging Spectroradiometer) is a key instrument aboard the Terra (EOS AM) andAqua (EOS PM) satellites. Terras orbit around the Earth is timed so that it passes from north to south across the equator in the morning, while Aqua passes south to north over the equator in the afternoon. Terra MODIS and Aqua MODIS are viewing the entire Earths surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths. These data improve our understanding of global dynamics and processes occurring in the oceans, and in the lower atmosphere. MODIS is playing a vital role to predict global change accurately.
  26. 26. Technical Information Orbit:705 km, 10:30 a.m. descending node (Terra) or 1:30 p.m. ascending node (Aqua), sun-synchronous, near-polar, circularScan Rate:20.3 rpm, cross trackSwath Dimensions:2330 km (cross track) by 10 km (along track at nadir)Telescope:17.78 cm diam. off-axis, afocal (collimated), with intermediate field stopSize:1.0 x 1.6 x 1.0 mWeight:228.7 kgPower:162.5 W (single orbit average)Data Rate:10.6 Mbps (peak daytime); 6.1 Mbps (orbital average)Quantization:12 bitsSpatial Resolution:250 m (bands 1-2) 500 m (bands 3-7) 1000 m (bands 8-36)Design Life:6 years
  27. 27. Cont….  MERIS is a programmable, medium-spectral resolution, imaging spectrometer operating in the solar reflective spectral range. Fifteen spectral bands can be selected by ground command.  The instrument scans the Earths surface by the so called "push- broom" method. Linear CCD arrays provide spatial sampling in the across-track direction, while the satellites motion provides scanning in the along-track direction.  MERIS is designed so that it can acquire data over the Earth whenever illumination conditions are suitable. The instruments 68.5° field of view around nadir covers a swath width of 1150 km. This wide field of view is shared between five identical optical modules arranged in a fan shape configuration.
  28. 28.  StatusOperational TypeImaging multi-spectral radiometers (vis/IR) Technical CharacteristicsAccuracy:Ocean colour bands typical S:N = 1700Spatial Resolution:Ocean: 1040m x 1200 m, Land & coast: 260m x 300mSwath Width:1150km, global coverage every 3 daysWaveband:VIS-NIR: 15 bands selectable across range: 390 nm to 1040 nm(bandwidth programmable between 2.5 and 30 nm) Earth TopicsLand ( Vegetation ), Ocean and Coast ( Ocean Colour/Biology ), Atmosphere ( Clouds/Precipitation )
  29. 29. Advanced Very High Resolution Radiometer - AVHRR  The AVHRR is a radiation-detection imager that can be used for remotely determining cloud cover and the surface temperature. Note that the term surface can mean the surface of the Earth, the upper surfaces of clouds, or the surface of a body of water. This scanning radiometer uses 6 detectors that collect different bands of radiation wavelengths as shown below. The latest instrument version is AVHRR/3, with 6 channels, first carried on NOAA-15 launched in May 1998.
  30. 30. Cha Resolutio nnel Waveleng Typical n at Num th (um) Use Nadir ber Daytime cloud and 1 1.09 km 0.58 - 0.68 surface mapping Land-water 2 1.09 km 0.725 - 1.00 boundaries Snow and 3A 1.09 km 1.58 - 1.64 ice detection Night cloud mapping, 3B 1.09 km 3.55 - 3.93 sea surfaceAVHRR/3 temperatur eChannel Night cloud mapping,Characteristics 4 1.09 km 10.30 - 11.30 sea surface temperatur e Sea surface
  31. 31. AATSR Advanced Along-Track Scanning Radiometer (AATSR) is one of the Announcement of Opportunity (AO) instruments on board the European Space Agency (ESA) satellite ENVISAT. It is the most recent in a series of instruments designed primarily to measure Sea Surface Temperature (SST), following on from ATSR-1 and ATSR-2 on board ERS-1 and ERS-2. AATSR data have a resolution of 1 km at nadir, and are derived from measurements of reflected and emitted radiation taken at the following wavelengths: 0.55 µm, 0.66 µm, 0.87 µm, 1.6 µm, 3.7 µm, 11 µm and 12 µm. Special features of the AATSR instrument include its use of a conical scan to give a dual-view of the Earths surface, on-board calibration targets and use of mechanical coolers to maintain the thermal environment necessary for optimal operation of the infrared detectors.
  32. 32. StatusOperationalTypeImaging multi-spectral radiometers (vis/IR) & Multipledirection/polarisation radiometersTechnical CharacteristicsAccuracy:Sea surface temperature: <0.5K over 0.5 deg x 0.5 deg (lat/long)area with 80% cloud cover Land surface temperature: 0.1K (relative)Spatial Resolution:IR ocean channels: 1km x 1km, Visible land channels: 1km x 1kmSwath Width:500 kmWaveband:VIS - NIR: 0.555, 0.659, 0.865 micrometers, SWIR: 1.6 micrometers,MWIR: 3.7 micrometers, TIR: 10.85, 12 micrometersEarth TopicsLand ( Vegetation ), Ocean and Coast ( Sea Surface Temperature ), Atmosphere ( Clouds/Precipitation )
  33. 33. Poseidon 2-Poseidon 3- RA 2 The Poseidon-2 altimeter is the main instrument on the Jason-1 mission. Derived from the Poseidon-1 altimeter on Topex/Poseidon, it measures sea level, wave heights and wind speed. It operates at two frequencies and is also able to estimate atmospheric electron content.Function Poseidon-2 measures range (the distance from the satellite to the Earths surface), wave height and wind speed.
  34. 34.  Principle The altimeter emits a radar beam that is reflected back to the antenna from the Earths surface.Poseidon-2 operates at two frequencies (13.6 GHz in the Ku band and 5.3 GHz in the C band) to determine atmospheric electron content, which affects the radar signal path delay. These two frequencies also serve to measure the amount of rain in the atmosphere. Technical data Poseidon-2, or SSALT (for Solid State ALTimeter), uses solid-state amplification techniques. Emitted Frequency (GHz)Dual-frequency (Ku, C) - 13.575 and 5.3Pulse Repetition Frequency (Hz)2060 interlaced {3Ku-1C-3Ku}Pulse duration (microseconds)105Bandwidth (MHz)320 (Ku and C)Antenna diameter (m)1.2Antenna beamwidth (degrees)1.28 (Ku), 3.4 (C)Power (W)7RedundancyYesSpecific featuresSolid-State Power Amplifier. Dual-frequency for ionospheric correction, High resolution in C band (320 MHz)
  35. 35. RA-2 Radar Altimeter 2 (RA-2) is an instrument for determining the two-way delay of the radar echo from the Earths surface to a very high precision: less than a nanosecond. It also measures the power and the shape of the reflected radar pulses. It is a nadir-looking pulse-limited radar altimeter based on the heritage of ERS-1 RA functioning at the main nominal frequency of 13.575 GHz (Ku Band), which has been selected as a good compromise between the affordable antenna dimension that provides the necessary gain and the relatively low attenuation which experience the signals propagating through the troposphere. ,
  36. 36. Status:OperationalType Radar altimeter Technical Characteristics AccuracyAltitude: better than 4.5cm, Wave height: better than 5% or 0.25mSpatial ResolutionSwath WidthWavebandMicrowave: 13.575Ghz (Ku-Band) & 3.2GHz (S-Band) ApplicationsSnow and Ice (Sea Ice) Atmosphere (Winds) Land (Topography/Mapping) Ocean and Coast (Ocean Waves,Ocean Currents and Topography)
  37. 37. Poseidon 3 The Poseidon-3 altimeter is the main instrument on the Jason-2 mission. Derived from the Poseidon-1 altimeter on Topex/Poseidon and Poseidon-2 on Jason-1, it measures sea level, wave heights and wind speed. It operates at two frequencies and is also able to estimate atmospheric electron content. Poseidon-2 being integrated on Jason-1. Poseidon-3 on Jason-2 is similar (Credits CNES/Alcatel) Function Poseidon-3 measures range (the distance from the satellite to the Earths surface), wave height and wind speed. (m)1.2Antenna beamwidth (degrees)1.28 (Ku), 3.4 (C)Power (W)7RedundancyYesSpecific featuresSolid-State Power Amplifier. Dual-frequency for ionospheric correction, High resolution in C band (320 MHz)
  38. 38. PrincipleThe altimeter emits a radar beam that is reflected back to the antenna from the Earths surface (see how altimetry works for details). Poseidon-3 operates at two frequencies (13.6 GHz in the Ku band and 5.3 GHz in the C band) to determine atmospheric electron content, which affects the radar signal path delay. These two frequencies also serve to measure the amount of rain in the atmosphere.Technical dataPoseidon-3, or SSALT (for Solid State ALTimeter), uses solid-state amplification techniques. Emitted Frequency (GHz)Dual-frequency (Ku, C) - 13.575 and 5.3Pulse Repetition Frequency (Hz)2060 interlaced {3Ku-1C-3Ku}Pulse duration (microseconds)105Bandwidth (MHz)320 (Ku and C)Antenna diameter
  39. 39. In-Situ Observations for SST
  40. 40. THE MAIN FAMILIES OF IN-SITU OBSERVING SYSTEMS Argo profiling floatsArgo profiling floats measuremainly Temperature andSalinity from sea surface to2000 m depth with good,consistent spatial resolution.
  41. 41.  Argo is an international collaboration that collects high-quality temperature and salinity profiles from the upper 2000m of the ice-free global ocean and currents from intermediate depths. At present there are three models of profiling float used extensively in Argo. All work in a similar fashion but differ somewhat in their design characteristics. At typically 10-day intervals, the floats pump fluid into an external bladder and rise to the surface over about 6 hours while measuring temperature and salinity.
  42. 42.  Satellites determine the position of the floats when they surface, and receive the data transmitted by the floats. The bladder then deflates and the float returns to its original density and sinks to drift until the cycle is repeated. Floats are designed to make about 150 such cycles.
  43. 43. Research vessels Research vessels deliverseveral high-accurate parameters(including Chlorophyll-a and Temperature)from sea surface to the oceanfloor, but with intermittent spatialcoverage.
  44. 44. Gliders Gliders provide physical data (Temperature, Salinity and Currents) as well as biogeochemical data (Chlorophyll-a, oxygen, nutrients,…) from surface to 1000 m below the surface, depending on the equipment. These instruments can be steered from shore via satellite.
  45. 45.  An underwater glider is a type of autonomous underwater vehicle (AUV) that uses small changes in its buoyancy in conjunction with wings to convert vertical motion to horizontal, and there by propel itself forward with very low power consumption.Gliders typically make measurements such as temperature, conductivity (to calculate salinity), currents, chlorophyll fluorescence, optical backscatter, bottom depth, and (occasionally) acoustic backscatter.
  46. 46.  They navigate with the help of periodic surface GPS fixes, pressure sensors, tilt sensors, and magnetic compasses. Vehicle pitch is controllable by movable internal ballast (usually battery packs), and steering is accomplished either with a rudder (as in Slocum) or by moving internal ballast to control roll . Buoyancy is adjusted either by using a piston to flood/evacuate a compartment with seawater (Slocum) or by moving oil in/out of an external bladder Commands and data are relayed between gliders and shore by satellite. Gliders vary in the pressure they are able to withstand. The Slocum model is rated for 200 meter or 1000 meter depths.
  47. 47. Bathythermographs (XBT)  Bathythermographs are launched from either research or commercial vessels and measure Temperature from the surface down to 450-750 m below sea surface
  48. 48. Surface MooringsSurface moorings measure a wide variety of sub-surfacevariables includingTemperature, Salinity,Currents overlong periods of time.These data are essentialfor model validation.
  49. 49.  Moorings include: an anchor — usually iron weights cables — typically made of steel, nylon, or Kevlar bottom floats — often air-filled glass balls, shrouded in plastic, which keep the mooring string upright, taut, and off the sea bottom release mechanisms — mechanical devices which break the morning chain and allow the instruments to float to the surface upon command by a science technician subsurface floats and/or surface buoys — commonly made of foam or other buoyant, non-compressible materials; also used to keep the mooring upright and support instruments
  50. 50.  Above the water, moored buoys may be mounted with meteorological sensors, communications systems (such as satellite or radio transmitters and receivers), and solar panels. Below the water line, buoys hold various instruments, including: current meters, temperature and pressure sensors, sediment traps, chemical sensors, power supplies, data recorders, and acoustic modems
  51. 51. Coastal Surface Electro-Optical-Mechanical (EOM) Mooring
  52. 52. Ferry Boxes  Ferry boxes are found on board ferries or regional ships. They measure Temperature, Salinity, Turbidity,  Chlorophyll, nutrient, Oxygen, pH and algal types.
  53. 53. Ferrybox derives its name from fitting ferries on regular crossings with a suite or “box” of autonomous sensors for measuring key ocean properties. Core measurements are temperature, salinity, chlorophyll-fluorescence and turbidity but can include other variables such as pCO2(the partial pressure of carbon dioxide), dissolved oxygen, macro-nutrients, pH and currents. These data, which mostly come from the upper few metres of the water column, are collected at high frequency (seconds to minutes) and subsets are sent in near real time via satellite communications to shore for remote system checks and to marine data centres for further dissemination. Other
  54. 54. Ferrybox systems have automated water samplingcapabilities for additional measurements such asalgal pigments. One key advantage of Ferryboxes isthat they are reliant on plentiful power suppliesfrom the ship, unlike other in-situ samplingplatforms which rely on the limited life-spans ofbatteries
  55. 55. Major Advantage of FerryBoxes are:-For automated ocean observing it soon became clear that monitoring of surface waters using buoys, piles and platforms with ins situ sensors is very expensive- enough energy on the ships --> more complicated analyser system can be used- sheltered conditions inside the ship --> sophisticated equipment can be installed- easy maintenance in the harbour --> no additional ship time is needed- the information from a transect is often better than from a single location
  57. 57. Why salinity is measured?  Sea Surface Salinity is a key parameter to estimate the influence of oceans on climate. Along with temperature, salinity is a key factor that determines the density of ocean water and thus determines the convection and re emergence of watermasses. The thermohaline circulation crosses all the oceans in surface and at depth, driven by temperature and salinity.  A global "conveyor belt" is a simple model of the large-scale thermohaline circulation. Deep-water forms in the North Atlantic, sinks, moves south, circulates around Antarctica, and finally enters the Indian, Pacific, and Atlantic basins. Currents bring cold water masses from North to South and vice versa.  This thermohaline circulation greatly influences the formation of sea ice at the world’s poles, and carries ocean food sources and sea life around the planet, as well as affects rainfall patterns, wind patterns, hurricanes and monsoons.
  58. 58. How is it measured ?  By satellite •Microwave radiometer (starting in 2009 with the launch of SMOS)  In situ techniques •Profiling floats •Moored buoys  Numerical models Models are crucial to estimate this parameter. With an ocean mixed-layer model (between 50 and 1000 m depth), Sea Surface Salinity can be estimated by modeling external (winds, evaporation/precipitation, river runoffs...) and internal (horizontal transport, vertical mixing,...) influences.
  59. 59. SALINITY Instrument Ocean Instrument Satellite Type Parameter Used Name Microwave •Atmospheric SSM/ITMI DMSP (NASA, radiometer water vapor AMSR-E USA) content MWR TRMM (NASA, •Atmoshperic JMR, AMR USA) water liquid Aqua (NASA, content (cloud) USA) + •Rain rates (developed by •Sea-ice JAXA, Japan) concentration, Envisat (ESA, type, extent Europe) •SST Jason-1, Jason-2 •Salinity (Cnes, France + NASA, USA)
  60. 60. Which Satellite Instruments are used for monitoring Salinity ?
  61. 61. TRMM Instruments TRMM Microwave Imager The Tropical Rainfall Measuring Missions (TRMM) Microwave Imager (TMI) is a passive microwave sensor designed to provide quantitative rainfall information over a wide swath under the TRMM satellite. By carefully measuring the minute amounts of microwave energy emitted by the Earth and its atmosphere, TMI is able to quantify the water vapor, the cloud water, and the rainfall intensity in the atmosphere.
  62. 62. Advanced Microwave Scanning Radiometer AMSR-E The Advanced Microwave Scanning Radiometer for EOS (AMSR-E) is a twelve-channel, six-frequency, total power passive-microwave radiometer system. It measures brightness temperatures at 6.925, 10.65, 18.7, 23.8, 36.5, and 89.0 GHz. Vertically and horizontally polarized measurements are taken at all channels.
  63. 63. AMSR-EIt will provide instantaneous measurements for the following data products:Rainfall over oceanRainfallSea surface temperature,Total integrated water vapor over the oceanTotal integrated cloud water over the oceanOcean surface wind speedSurface soil wetnessSea ice concentrationSnow depth over sea iceSea ice drift .Snow water equivalent over land.
  64. 64. Which In- Situ Instruments areused for monitoring Salinity?
  65. 65. THE MAIN FAMILIES OF IN-SITU OBSERVING SYSTEMS Argo profiling floatsArgo profiling floats measure mainly Temperature andSalinity from sea surface to2000 m depth with good,consistent spatial resolution.
  66. 66. GlidersGliders provide physical data (Temperature, Salinity and Currents) as well as biogeochemical data (Chlorophyll-a, oxygen, nutrients,…) from surface to 1000 m below the surface, depending on the equipment. These instruments can be steered from shore via satellite.
  67. 67. Surface MooringsSurface moorings measure a wide variety of sub-surface variables including Temperature,Salinity, Currents overlong periods of time.These data are essentialfor model validation.
  68. 68. Ferry boxes  Ferry boxes are found on board ferries or regional ships. They measure Temperature, Salinity, Turbidity,and Chlorophy ll, nutrient, Oxygen, pH and algal types.
  69. 69. CURRENTSWhy measure currents? By transporting heat and energy, ocean currents play a major role in shaping the climate of Earth’s many regions. Surface currents (restricted to the upper 400 m of the ocean) are generally wind-driven and develop their typical clockwise spirals in the northern hemisphere and counter-clockwise rotation in the southern hemisphere (for warm currents). Deep ocean circulation is the result of a number of factors including temperature and salinity variations in water masses, shorelines, subsurface topography, tides, etc. Currents are extremely important for maintaining the earths heat balance. Currents known as upwelling also bring bring cold, nutrient-rich water from the depths up to the surface.
  70. 70. How current is measured ? By satellite Altimeters (for geostrophic currents) Altimeters +scatterometers (to see surface currents + winds)In situ techniques Argo (deep ocean currents) Drifting buoys Numerical models One of the important outputs of ocean models are the currents, at any depth. Forecasting currents is one of the main applications of numerical models.
  71. 71. Ocean parameterInstrument type Instrument name Satellite measuredAltimeter •Sea-surface height Poseidon-2 Jason-1 (CNES, •Ocean surface wind RA-2 France + NASA, speed Poseidon-3 USA) •Wave height Envisat (ESA, •Sea ice Europe) Jason-2 (CNES, France + NASA, NOAA, USA + Eumetsat, Europe)Scatterometer •Wind speed and ASCAT Metop (Eumetsat, heading (10 m above Europe) ocean surface) •Rain •Sea ice concentration
  72. 72. THE MAIN FAMILIES OF IN-SITU OBSERVING SYSTEMS Argo profiling floatsArgo profiling floats measure mainly Temperature andSalinity from sea surface to2000 m depth with good,consistent spatial resolution.
  73. 73. Surface mooringsSurface moorings measure a wide variety of sub-surface variables including Temperature,Salinity, Currents overlong periods of time.These data are essentialfor model validation.
  74. 74. Sea IceWhy We measure Sea Ice?  Ice covers a substantial part of the Earths surface and is one of the major factor in commercial shipping and fishing industries, Coast Guard and construction operations, and global climate change studies.
  75. 75. How Sea Ice is measured? By satellite Microwave radiometers (concentration, drift) Microwave scatterometers (extent, edge, type) Infrared sensors (extent) SAR sensors Altimeters (extent, iceberg detection, thickness, edge) In-situ techniques Ice buoys (temperature, mass, drift) Numerical models Ocean models are capable of taking sea ice into account. Ice models are coupled with ocean models. The ocean model provides a model of ice, sea state (temperature, salinity, currents) and other observations necessary to calculate the evolution of parameters such as thickness, velocity, concentration, drift…
  76. 76. Ocean parameterInstrument type Instrument name Satellite measuredSpectroradiometer Aqua (NASA, USA) MODIS Envisat (ESA, Europe) •Sea Ice Cover MERISMicrowave SSM/ITMI DMSP (NASA, TRMM (NASA,radiometer •Sea-ice AMSR-E Aqua (NASA,+ concentration, MWR (developed by JAXA, type, extent JMR, AMR Japan) Envisat EU Jason-1, Jason-2 (Cnes, France + NASA,Altimeter •Sea-surface height Poseidon-2 Jason-1 (CNES, France + •Ocean surface RA-2 NASA, USA) wind speed Poseidon-3 Envisat (ESA, Europe) •Wave height Jason-2 (CNES, France + NASA, NOAA, USA + •Sea ice Eumetsat, Europe)Scatterometer •Sea ice ASCAT Metop (Eumetsat, Europe) concentrationSynthetic Aperture Radarsat-1, Radarsat-2, •Sea ice monitoring CanadaRadar (SAR) Envisat, Europe
  77. 77. ASCAT ASCAT stands for Advanced SCATterometer. It is a microwave radar instrument onboard the EUMETSAT polar orbit METOP satellites, and it estimates wind (speed and direction) over the ocean, retrieves soil moisture and identifies snow and ice. Scatterometers are active radar instruments and therefore both emit and receive microwave radiation. This radiation has the advantage of not being affected by clouds and this is why scatterometers are known to be able to scan the surface in almost all weather conditions. With regard to wavelength, there are in fact two types of scatterometers: C band (ASCAT) and Ku band (OSCAT, the scatterometer onboard the polar orbit Indian Space Research Organization OceanSat2 satellite, not used in this case study.
  78. 78.  ASCAT emits microwave radiation with a wavelength of 5.7 cm. This radiation is resonant with centimeter-scale ocean waves of comparable wavelength due to the so-called Bragg scattering mechanism, and is sent back to the sensor. This backscatter radiation coming from the water surface can then be processed in order to compute near-surface ocean wind speed and direction. This capability relies on the assumption that the small-scale ocean waves responsible for the backscatter are in equilibrium with the wind. As wind speed increases, surface roughness also increases and more microwave radiation is scattered towards the direction of the radar source
  79. 79.  ASCAT is composed of two sets of three antennas that cover two distinct areas located to the left (one set) and to the right (the other set) of the satellite track, therefore being considered a double swath scatterometer unlikeQuikscat or OSCAT, which are single swath scatterometers.
  80. 80. In- Situ Observations -Icebuoys (temperature, mass, drift) Ice buoys have been used extensively in Arctic and Antarctic regions to track ice movement and are available commercially for deployment by ships or aircraft. Such buoys are equipped with low temperature electronics and lithium batteries that can operate at temperatures down to -50°C. In addition to the regularly-computed Argos locations the ice buoys can be equipped with satellite navigation receivers (e.g. GPS) which can compute even more accurate positions.
  81. 81. Current Buoy Positions
  82. 82. SEA LEVELWhy measure sea level? The sea surface is anything but flat. There are bumps and troughs , all due to different physical characteristics such as gravity, currents, temperature and salinity… Since we do not know much about the ocean’s bottom, it is easier to refer to “sea height” instead of sea depth. Sea level is measured with reference to a fixed surface height. By analyzing variations from this reference point, scientists determine ocean circulation (currents and eddies at the edges of holes and bumps), seasonal or inter-annual variations, or even longer periods (long-term rise in sea level).
  83. 83.  How is it measured?By satellite AltimetersNumerical models All numerical models simulate sea level.
  84. 84. Ocean parameterInstrument type Instrument name Satellite measuredAltimeter •Sea-surface height Poseidon-2 Jason-1 (CNES, •Ocean surface RA-2 France + NASA, wind speed Poseidon-3 USA) •Wave height Envisat (ESA, •Sea ice Europe) Jason-2 (CNES, France + NASA, NOAA, USA + Eumetsat, Europe)
  85. 85. SEA LEVEL MEASUREMENTS TIDE GAUGES NEW GEODETIC TECHNIQUESDevelopments in new geodetic techniques (CGPS,DORIS, Absolute Gravity) are progressing for monitoringvertical land movements. This will eventually provideestimates of ‘absolute’ sea level change.99
  86. 86. WINDWhy measure wind Surface winds, combined with other atmospheric forces (solar energy, precipitation rate, evaporation rate) are all responsible for the movement of water masses in the ocean, and are thus responsible for ocean currents. Marine winds shape the ocean, and can cause waves as high as a mountain to swell during a storm. They are the source of many legends and color the moods of seafarers around the world.
  87. 87. How is it measured?By satellite Microwave radiometers Microwave scatterometers SAR AltimetersNumerical models Numerical weather forecasting models make it possible to understand sea surface winds. They are many of these models in operation today.
  88. 88. measuredMicrowave SSM/ITMI DMSP (NASA, Microwave •Atmospheric waterradiometer AMSR-E USA) radiometer vapor content MWR TRMM (NASA, •Atmoshperic water JMR, AMR USA) liquid content Aqua (NASA, USA) (cloud) + (developed by •Rain rates JAXA, Japan) •Sea-ice Envisat (ESA, concentration, Europe) type, extent Jason-1, Jason-2 •SST (Cnes, France + •Salinity NASA, USA)Altimeter •Sea-surface height Poseidon-2 Jason-1 (CNES, Altimeter •Ocean surface RA-2 France + NASA, wind speed Poseidon-3 USA) •Wave height Envisat (ESA, •Sea ice Europe) Jason-2 (CNES, France + NASA, NOAA, USA + Eumetsat, Europe)Scatterometer •Wind speed and ASCAT Metop (Eumetsat, Scatterometer heading (10 m Europe) above ocean surface) •Rain •Sea ice concentration
  89. 89. BIOGEOCHEMISTRYWhy measure biogeochemistry/ocean colour?  Phytoplankton (vegetable plankton) is the first link in the ocean’s food chain, and is the main source of food for most fish. Phytoplankton contains chlorophyll, which instigates photosynthesis in the ocean, absorbs atmospheric CO2 and releases oxygen in sunlight. More than any land-based plant, phytoplankton is the biggest producer of oxygen on Earth. Knowing the chlorophyll content of the ocean’s surface levels is an important way to measure primary production, as well as of global ocean health.
  90. 90. How is it measured? By satellite Spectroradiometers
  91. 91. OceanInstrument type parameter Instrument name Satellite measuredSpectroradiomet •Chlorophyll Aqua (NASA,er content USA) •Organic and MODIS Envisat (ESA, mineral content MERIS Europe) •Sea surface temperature •Sea Ice Cover
  92. 92. WATER PARAMETERS to DETERMINEWATER QUALITY Remote sensing techniques can be use to assess several water quality parameters (i.e., suspended, sediments (turbidity), chlorophyll, temperature optical and thermal sensors on boats, aircraft, and satellites provide both spatial and temporal information needed to understand changes in water quality parameters necessary for developing better management practices to improve water quality.
  93. 93. The color of the Earth’surface, especially thecolor of the ocean, resultsprimarily from biologicalprocesses.Measuring the absorptionand backscatteringcharacteristics of oceansurface, we can estimatethe concentrations ofdifferent kinds of mattersuspended in seawater,including phytoplanktoncells.
  94. 94. Remote sensing of indicators of water quality offersthe potential of relatively inexpensive, frequent, andsynoptic measurements using sensors aboard aircraftand/or spacecraft.
  95. 95. Suspended sediments, chlorophylls, DOM,temperature, and oil are water quality indicators thatcan change the spectral and thermal properties ofsurface waters and are most readily measured by remotesensing techniques.
  96. 96. Example of Level 2 data:MODIS Total Suspended Solids , 2000 December 6, 17:05
  97. 97. SUSPENDED SEDIMENTSuspended sediments are defined as solid particles transported ina fluid media or found in deposit after transportation by flowingwater, wind, glacier and gravitational action. Theirconcentration in a water body is affected by many factors. Inrivers, the concentration depends on the water’s flow rate,turbidity, soil erosion, urban runoff, and wastewater and septicsystem effluent, while in lakes, decaying plants and animals,bottom-feeding fish, and wind/wave action play a larger role. Ingeneral, the reflectance of water increases with increasedsuspended sediment concentrations (positive correlation) anddecreases with increased salinity (negative correlation).
  98. 98. Dissolved Oxygen Measures of dissolved oxygen (DO) refer to the amount of oxygen contained in water, and define the living conditions for oxygen-requiring (aerobic) aquatic organisms. Oxygen has limited solubility in water, usually ranging from 6 to 14 mg L -1 . DO concentrations reflect an equilibrium between oxygen-producing processes (e.g. photosynthesis) and oxygen-consuming processes
  99. 99.  Oxygen solubility varies inversely with salinity, water temperature and atmospheric and hydrostatic pressure. Dissolved oxygen consumption and production are influenced by plant and algal biomass, light intensity and water temperature (because they influence photosynthesis), and are subject to diurnal and seasonal variation
  100. 100. CHLOROPHYLL Nutrients and substances are required for a healthy aquatic environment, an excess of these inputs leads to nutrient enrichment and eutrophication of the lake. Eutrophication of a water body is usually quantified in terms of the concentration of the chlorophyll contained in the algal/plankton.
  101. 101. TurbidityTurbidity is another commonly used water quality variable. It is a measure of optical scattering in the water and, hence, closely related to the amount of suspended particles. I.e. if the amount of chl a (phytoplankton) and/or suspended sediments is high, the turbidity value is also high. Typically, a single band in the visible or near- IR region can be used to map turbidity with reasonable accuracy (Lindell et al., 1999)
  102. 102. The first satellite based sensor devoted to water quality measurements was the Coastal Zone Color Scanner (CZCS) . Then,SeaWiFS (Sea-viewing Wide Field Sensor,Airborne instruments such as AISA (Airborne ImagingSpectrometer for Application), CASI (Compact AirborneSpectrographic Imager) and HyMapMODIS and MERISAVHRRALOS satellite
  103. 103. Examples for theMonitoring Critical Marine Issuses
  104. 104. Ship Based Oil Pollution Monitoring
  105. 105. Marine Pollution Sources Oil Pollution Heavy Metals and their products Bioaccumulation Disposal of Radioactive Materials Discharge of Sewage Harmful Algal Blooms 4
  106. 106. Major inputs of Oil to the MarineEnvironment  37% comes from industrial wastes, reach the sea, via storm water drain, creeks, sewage and rivers.  12% from ship accidents involving tankers.  33% from vessels illegal operations  9% absorbed from atmosphere.  7% comes from natural sources like fissures from sea bed.  2% during explorations and 4
  107. 107. Ship Based Oil Pollution MARPOL defines oil as; petroleum in any form including crude oil, fuel oil, sludge, oil refuse and refined products (other than petrochemicals which are subject to the provisions of Annex II of the present Convention) 5
  109. 109. 3.1 Why Ships Discharge Illegal Oil Waste andOily Water to the Sea ? Three categories of oily waste generally accumulate onboard especially on large and very old vessels  Bilge water  Sludge  Oil cargo residue
  110. 110. Illegal Oil Discharge Source: Bilge Waste  Machinery spaces especially on large commercial vessels generate oily waste products and leakage everyday.
  111. 111. Illegal Oil Discharge Source: Sludge Waste  In order to prevent damage to engine systems and improve combustion, the fuel should be purified. After purifying the residues and oily water’re called as sludge.
  112. 112. Illegal Oil Discharge Source: Oil Cargo Residue WasteTankers carry oil and oily product in bulk. After eachchange of cargo type, cargo tanks should be cleaned.Tank washing operations are carried out by steam waterfor cleaning cargo tanks and these washing and cleaningoperations produce oily waste water.
  113. 113.  The best method for dealing with bilge water, sludge and slop is storing and delivering ashore as disposal but storing these oily water and oily products on board causes less cargo transportation and too much cost for delivering the oily products a shore as disposal. These are the great reason why ships make illegal discharging.
  114. 114. Ship Accidents, Involving Tankers Cause SeriousOil Pollution. 131
  115. 115. Any Accidents with Oil Pollution
  116. 116. GROUNDING
  117. 117. COLLISION
  118. 118. FIRE Exxon Valdez, March 1989, Alaska Mega Borg, June 1990, Texas Cibro Savannah, March 1990, New JerseyBurmah Agate, November 1979, Gulf of Mexico
  119. 119. SINKING Argo Merchant, December 1976, Nantucket Island
  120. 120. Different Tools to Detect and Monitor Oil SpillsThere are different remote sensing applications for detection of oil pollution/spillson sea surface. In the electromagnetic spectrum, Oil gives different responses andsignatures to radiation from different wavelengths. Different tools to detect andmonitor oil spills:– VesselsRemains necessary in case of oil sampling, but they can cover a very limited area.-Airborne  SLAR (Side looking airborne Radar)  LFS (Laser Fluorosensor)  MWR (Microwave radiometry)  IR/UV (Infrared/ultraviolet line scanner)  FLIR (Forward looking infrared)  Camera/video - Satellite  SAR (Synthetic Aperture Radar)  Optical Sensors
  121. 121.  ULTRAVIOLET Detect oil spills at thin layers, not usable at night, and wind slicks, sun glints and biogenic material. VISIBLE In the visible region of EM spectrum oil has a higher surface reflectance than water and absorbs energy showing black or brown signatures, limited and cause mistakes due to atm. condition . 7 THERMAL INFRARED Emmisivity difference between oil (0.972 μm) and water (0.993 μm) leads to different brightness temperatures, Therefore, oil layers appear colder than water in thermal images. For thickness of oil slicks, as the thickness increases they appear hotter in the infrared images Limited for very thin oil slicks. 7
  122. 122. Microwave Sensors - RADAR Microwave sensors are the most applicable tools for oil slick monitoring since they are not affected by clouds, haze, weather conditions and day/night differences.7 Radio Detection and Ranging (RADAR) operates in the microwave portion of the electromagnetic spectrum.
  123. 123. Synthetic Aperture Radar (SAR) Most common microwave sensor for oil slick detection is SAR. The main mechanism in detection of oil slicks is the dampening effect of oil on water. Dampening of sea waves results in reduced radar return from the affected area, so that oil slicks appear as relatively dark features on the SAR scenes.9G. Franceschetti,2002 SAR Raw Signal Simulation of Oil Slicks in Ocean Environments 2002Pic Ref: Yonggang. J, First Institute of Oceanography SOA.2009
  124. 124. SAR can be used on both airborne and space borne observationalplatformsAdvantage Day & night observation. All-weather capability. High spatial resolution. Wide area coverage. Pic Ref: Yonggang. J, First Institute of Oceanography SOA.2009Disadvantage No wind. Strong winds (above 13m/sec). Look – alikes.
  125. 125. Remote Sensing of MarineResources Fish Stock Managment protection and the sustainable management of living marine resources in particular for aquaculture, fishery research or regional fishery Fisheries Research Assess and monitorthe level of contaminants in fish Favorable area for fish farms
  126. 126. Need Parameters Temperature Sea level Currents Chlorophyll-a Dissolved oxygen Nutrients
  127. 127. COASTAL & MARINE ENVIRONMENT Physical and marine biogeochemical components are useful for water quality monitoring and pollution control Sea level rise helps to predictcoastal erosion. Sea surface temperature is one of the primary physical impacts of climate change and many marine ecosystems in seas are affected by rising sea temperature. Currents are useful for selecting locations for offshore windmill parks or thermal energy conversion field
  128. 128. Requested Parameters Temperature Salinity Currents Sea Level Chlorophyll-a Dissolved oxygen Nutrients
  129. 129. WEATHER, CLIMATE & SEASONAL FORECASTING Physical parameters of the oceans surface are used as boundary conditions for atmospheric models. Changes in sea ice extent, concentration and volume are signals used to detect global warming for instance.
  130. 130.  Mean of Maps of Sea Level Anomalies, El Niño area, during November 1997.
  131. 131.  Short and Medium Weather forecasting Seasonal Forecast Climate Change Future Sea Levels and Snow – Ice melting and effects on Global Warming
  132. 132. Requested Parameters Temperature Salinity Currents Sea Level Sea Ice
  133. 133. Conclusion Studying Remote sensing techniques for monitoring Earth Enviroment without ocean parameters and water quality parameters are not enough.
  134. 134. M/T Independenta, Tanker Accident,Big explosion, fire, pollution and tanker wreck for years at İstanbul Strait Thank You, Any Question?