This document discusses characterization of aerosols using Aerosol Optical Depth (AOD) over Pakistan by analyzing data from MODIS, CALIPSO, and AERONET. It provides background on aerosols and their impact on climate, describes various satellite and ground-based instruments used to measure aerosols including MODIS, CALIPSO, and AERONET, and presents AOD data from these sources over Pakistan during dust storm events in April 2015.

1. Characterization of Aerosols using
Aerosol Optical Depth (AOD) over
Pakistan by exploring MODIS,
CALIPSO and AERONET Data
Lokhaze Ali
PhD Student NUST

2. +2.50C
+1.50C
+1.90C
Ref: Dr. G Rasul (PMD),
2014
Pakistan 2050
The Deciding Factors
for Climate Change:
• Temperature
• Precipitation
• Wind Speed
2#Aerosols

3. Weather Systems Tracks
2010, 2011 & 2014
3
Ref: Dr Hanif (PMD), 2014
#Aerosols

4. 4#Aerosols

5. Aerosols
Least Understood Components
Aerosols play an
important role in our
climate system by means
of their direct and indirect
impacts, yet, they are still
one of the least
understood components
of the global climate
system…
Intergovernmental Panel
on Climate Change
(IPCC) 2007, 2013…
#Aerosols 5

6. IPCC 2013
Fifth Assessment Report - AR5
6#Aerosols

7. IPCC 2013
Fifth Assessment Report - AR5
7#Aerosols

8. Aerosols
• Aerosols are minute
particles suspended
in the atmosphere
• Adverse effect on
human health in
urban environments
• Effective pathways
for deposition of
pollutants
• Scatter and absorb
radiation impacting
heat balance of the
atmosphere
8#Aerosols

9. Aerosols can alter Cloud Properties
• Aerosols act as tiny “seeds”
called Cloud Condensation
Nuclei (CCN's)
• Clouds form when enough
water vapor condenses
• Aerosols play a critical role
• Without aerosols in the air,
there would be far fewer
clouds
• High amounts of aerosols,
clouds will have more
droplets than normal
• Droplets are smaller and
more numerous, clouds last
longer
• Clouds owe their
existence to Aerosols 9#Aerosols

10. Remote Sensing
Clouds & Aerosols
• Nucleation
• Hydrophilic/Hydr
ophobic Aerosols
• Size/Shape/Distri
bution of
Aerosols
10#Aerosols

11. Saharan Dust
• Dust from Sahara Desert
• Transported across the Atlantic
Ocean
• Supplies iron to the underlying
ocean surface waters
• Occasionally limits visibility in
Florida and the Caribbean
• Possibly fertilizes the Amazon
basin
11#Aerosols

12. Saharan Dust (Pink Color) travelling
from Lybia to Italy and Greece
#Aerosols 12

13. Arctic from 1913 to 2012
• Greenhouse gas
warming alone three
degrees Celsius in
the Arctic over the
last 100 years
• Actual observed
warming is around
1.2 degrees Celsius
• Aerosols offset about
60 per cent of the
warming
13#Aerosols

14. Levels of Data
Level 1B Level 2 Level 3
Calibration to
Radiance
Aerosol
Retrieval
Algorithm
Spatial & Temporal
Averaging
Ref: Pawan Gupta (NASA), 2015 #Aerosols 14

15. Aerosol Optical Depth (AOD)
Aerosol optical depth is a
measure of radiation
extinction due to scattering
and absorption by aerosol
particles in the atmosphere.
• Particles (dust, smoke,
pollution)
• Dimensionless number
• Amount of aerosol in the
vertical column of
atmosphere over/below
the observation location
15#Aerosols

16. Aerosol Optical Depth
Deep Blue AOD
• Deep Blue AOD at 550
nm for MODIS calculates
AOD over bright areas
such as deserts where the
standard MODIS AOD
algorithm does not work.
• Surface Reflectance
greater than 0.15 and for
coarse particles
• Lower surface reflectance
in the blue part of the
visible spectra than in the
red part
(Ref: Dr. Farrukh Chishtie
(IST), 2015) #Aerosols 16

17. Aerosol Robotic Network
AERONET
• Sunphotometer is used
to measure the
extinction of direct beam
spectral solar radiation
• AERONET serve as
validation tool for
satellite aerosol product
• Robots with a data
logger, data
transmission device,
batteries, solar panels,
and antenna for data
transmission
• Karachi & Lahore
Robotic Arm tracking
the Sun
AERONET Pad
#Aerosols 17

18. The Lidar
• Lidar (light detection and
ranging) is an active
remote sensing technique
for observing the
distribution of molecules
and particles in the
atmosphere as a function
of height by means of the
light they backscatter from
a laser beam.
• The CALIPSO spacecraft
uses an innovative lidar
and imaging system to
reveal the secrets of 18#Aerosols

19. CALIPSO
(Cloud Aerosol Lidar and Infrared
Pathfinder Satellite Observations)
• Cloud-Aerosol Lidar with
Orthogonal Polarization
(CALIOP)
• CALIOP is a two-wavelength
polarization-sensitive lidar
that provides high-resolution
vertical profiles of aerosols
and clouds
• CALIOP utilizes three
receiver channels: one
measuring the 1064 nm
backscatter intensity and
two channels measuring
orthogonally polarized
components of the 532 nm
backscattered signal
#Aerosols 19
Arizona Fires June 3, 2011

20. A-Train Constellation
• A-Train of satellites circles
Earth, about eight-sixteen
minutes elapse between the
times when the first satellite
(Aqua) and the last (Aura)
pass over any given spot.
• String of satellites stretches
across 3,000 kilometers
• CloudSat flies in front of
CALIPSO, only around 93.8
kilometers
• Distance corresponds to an
average delay of only 12.5
seconds between lidar and
radar measurements
#Aerosols 20

21. Vertical Profile of Atmosphere
CALIPSO/Aeronet Sunphotometers/Ground Based Lidars
21#Aerosols

22. Monthly and Seasonal AOD
22#Aerosols

23. CALIPSO - Data Availability Site
NASA
#Aerosols 23

24. Selection of Path
#Aerosols 24

25. Precipitation Outlook - PMD
#Aerosols 25

26. CALIPSO over Pakistan
#Aerosols 26

27. CALIPSO Data
2-9-2014
#Aerosols 27

28. Pakistan Floods 2014
#Aerosols 28

29. Fog - WorldView
#Aerosols 29

30. Sensor : AVHRR
Satellite : METOP-1
Date : 30-12-2014
Time : 16 : 25 : 00 GMT
#Aerosols 30

31. CALIPSO Comparison
#Aerosols 31

32. Dust Storm 2nd April 2015
#Aerosols 32

33. Dust Storm 3rd April 2015
#Aerosols 33

34. Sensor : MODIS
Satellite : TERRA
Date : 03-04-2015
Time : 06 : 10 : 30 GMT
#Aerosols 34

35. Dust Storm 3rd April, 2015
#Aerosols 35

36. Dust Storm 4th April 2015
#Aerosols 36

37. Dust Storm 5th April 2015
#Aerosols 37

38. Dust Storm 2nd -7th April 2015
#Aerosols 38
02-04-2015 03-04-2015 04-04-2015
05-04-2015 06-04-2015 07-04-2015

39. Dust Storm 2nd -15th April 2015
AOD 550 nm (Deep Blue)
#Aerosols 39
2nd-8th April 2015
2nd-15th April 2015

40. HYSPLIT Model
Backward Trajectory
#Aerosols 40
2nd April 2015 8th April 2015

41. Important Data Links
• AERONET (Aerosol Robotic Network)
http://aeronet.gsfc.nasa.gov/
• LAADS Web (Level 1 and Atmosphere Archive and
Distribution System)
http://ladsweb.nascom.nasa.gov/data/search.html
• CALIPSO - KML/KMZ Data using Expedited Data
http://www-calipso.larc.nasa.gov/products/kmz_exp/index.php
• NASA EOSDIS WorldView
https://earthdata.nasa.gov/labs/worldview/
• GIOVANNI (The Bridge between Data & Science
http://giovanni.gsfc.nasa.gov/giovanni/
• GIOVANNI Air Quality
http://gdata1.sci.gsfc.nasa.gov/daac-
bin/G3/gui.cgi?instance_id=Air_Quality
#Aerosols 41

42. 42#Aerosols