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Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values
Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values
Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values
Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values
Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values
Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values
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Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values

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Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values

Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values

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  1. Evaluating the effect of soil moisture, surface temperature and humidity variations on MODIS-derived NDVI values Term Project Report Environmental Remote Sensing and Satellite Image Processing WEN507 Prepared by: Ashraf A. Hasania Wafa F.Al Yamani Yehia Eissa Yomna Mahmoud Ibrahim Hassan
  2. AMSR-E Overview AMSR-E stands for Advanced Microwave Scanning Radiometer- Earth Observing Systems, which is a twelve-channel, six-frequency, dual-polarized,passive-microwave radiometer system.[1] It is one of the instruments carried by Nasa’s Aqua satellite project[2]. AMSR-E detects faint microwave emissions from the Earth's surface and atmosphere[3].The AMSR-E instrument provides measurements of terrestrial, oceanic, and atmospheric parameters for the investigation of global water and energy cycles, including precipitation rate, sea surface temperature, sea ice concentration, snow water equivalent, soil moisture, surface wetness, wind speed, atmospheric cloud water, and water vapor[4]. AMSR-E The AMSR-E instrument aboard Aqua measures brightness temperatures at six frequencies (6.92, 10.65, 18.7, 23.8, 36.5, and 89.0 GHz) with vertical and horizontal polarizations at each frequency for a total of 12 channels. It achieves global swath coverage every two days or less, separately for ascending and descending passes, except for a small region near the poles. The mean footprint diameter ranges from 60km at 6.92 GHz to 5km at 89 GHz. The AMSR-E land surface products of surface soil moisture, vegetation water content and surface temperature are available on a daily basis in 25km Equal-AreaScalable Earth grid (EASE grid) with a global cylindrical, equal area projection true at 300N and 300S[8]. AMSR-E improves upon past microwave radiometers. The spatial resolution of AMSR-E data doubles that of Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I) data. Also, AMSR-E combines into one sensor all the channels that SMMR and SSM/I had individually [1]. The following table compares operating characteristics of AMSR-E with previous sensors The following table lists the pertinent performance characteristics of AMSR-E. Table1: AMSR-E Performance Characteristics[1] Quantifying Bit Number 12-bit Center Frequency (GHz) 6.925 10.65 18.7 23.8 36.5 89.0 Bandwidth (MHz) 350 Sensitivity (K) 0.3 Mean Spatial Resolution (km) 56 10-bit 100 200 400 1000 3000 0.6 38 21 1.1 24 12 5.4
  3. MODIS “MODIS is an Earth sciences instrument package aboard two different satellites, Terra and Aqua in similar but counter rotating orbits. The first MODIS Flight Instrument, ProtoFlight Model or PFM, is aboard the Terra (EOS AM-1) spacecraft. Terra successfully launched on December 18, 1999. The second MODIS flight instrument, Flight Model 1 or FM1, is aboard the Aqua (EOS PM-1) spacecraft; it was successfully launched on May 4, 2002. These MODIS instruments offer an unprecedented look at terrestrial, atmospheric, and ocean phenomenology for a wide and diverse community of users throughout the world” [5]. Radiometric Characteristics Unlike other satellite imagery and products, MODIS data is systematically converted into derived atmospheric, oceanic, and terrestrial products. The MODIS surface reflectance product is part of the latter. All seven land bands are corrected for atmospheric effects with an algorithm that uses aerosol and water vapor information collected by the sensor. The algorithm corrects for thin cirrus clouds, aerosols, and atmospheric gasses. The result is an estimation of surface reflectance as if it had been measured on the surface, without the effects of atmospheric absorption or scattering. [9] The table below describes wavelengths represented by the 36 bands and their applications included here: Table2: wavelengths represented by the 36 bands and their applications [9] Primary Use Band Bandwidth1 (nanometer) Spectral Required Radiance2 SNR3 Land/Cloud/Aerosols Boundaries Land/Cloud/Aerosols Properties 1(red) 2(NIR) 3(blue) 4(green) 5(SWIR) 6(SWIR) 7(SWIR) 8 9 10 11 12 13 14 15 16 17 18 19 620 - 670 841 - 876 459 - 479 545 - 565 1230 - 1250 1628 - 1652 2105 - 2155 405 - 420 438 - 448 483 - 493 526 - 536 546 - 556 662 - 672 673 - 683 743 - 753 862 - 877 890 - 920 931 - 941 915 - 965 21.8 24.7 35.3 29 5.4 7.3 1 44.9 41.9 32.1 27.9 21 9.5 8.7 10.2 6.2 10 3.6 15 128 201 243 228 74 275 110 880 838 802 754 750 910 1087 586 516 167 57 250 Band Bandwidth1 Spectral Required Ocean Color/ Phytoplankton/ Biogeochemistry Atmospheric Water Vapor Primary Use
  4. (micrometer) Surface/Cloud Temperature Atmospheric Temperature Cirrus Clouds Water Vapor Cloud Properties Ozone Surface/Cloud Temperature Cloud Top Altitude 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Radiance2 (W/m2 -µm-sr) NE[delta]T(K)4 3.660 - 3.840 3.929 - 3.989 3.929 - 3.989 4.020 - 4.080 4.433 - 4.498 4.482 - 4.549 1.360 - 1.390 6.535 - 6.895 7.175 - 7.475 8.400 - 8.700 9.580 - 9.880 10.780 - 11.280 11.770 - 12.270 13.185 - 13.485 13.485 - 13.785 13.785 - 14.085 14.085 - 14.385 0.45(300K) 2.38(335K) 0.67(300K) 0.79(300K) 0.17(250K) 0.59(275K) 6 1.16(240K) 2.18(250K) 9.58(300K) 3.69(250K) 9.55(300K) 8.94(300K) 4.52(260K) 3.76(250K) 3.11(240K) 2.08(220K) 0.05 2 0.07 0.07 0.25 0.25 150(SNR) 0.25 0.25 0.05 0.25 0.05 0.05 0.25 0.25 0.25 0.35 MODIS has spatial resolutions of 250m (bands 1-2), 500m (bands 3-7), and 1000m (bands 8-36) [9] AMSR-E and MODIS sensors differences Though lower in spatial resolution than MODIS optical bands, AMSR-E microwave measurements are typically less affected by clouds, water vapor, aerosol or solar illumination, making them complementary to MODIS real time measurements over regions of clouds and haze [6]. In cloudy area of the Earth, MODIS limits the sensor’s ability to quantify biophysical processes in heterogeneous landscape. A passive microwave sensor AMSR-E is not subject to cloud contamination although its spatial resolution is relatively coarse [7]. References: [1] http://nsidc.org/data/docs/daac/amsre_instrument.gd.html [2] http://aqua.nasa.gov/about/ [3] http://sharaku.eorc.jaxa.jp/AMSR/ov_amsre/index.html [4] http://nsidc.org/data/amsre/ [5] http://10ksnookers.blogspot.com/2008/03/what-is-modis.html [6] http://eastfire.gmu.edu/temp/eastfirewatch/homemain_files/DasguptaSPIE.pdf [7] Gonzales, W. T. Blending MODIS and AMSR_E to predict daily land surfacewater coverage. Tokyo: Institute of Industrial Science. [8] J.Qua, S. D. Combining MODIS and AMSR_E based vegetation moisture retrievals for improved fire risk monitoring. USA: George Mason University. [9] http://www.landcover.org/library/guide/techguide_modis.pdf

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