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METR155: Using Satellite Remote Sensing in Climate Model – focus on Urban
Menglin Jin, Professor Department of Meteorology
San Jose State [email protected]
http://www.usgcrp.gov/usgcrp/images/ocp2003/ocpfy2003-fig3-4.htm
The past, present and future of climate models
During the last 25 years, different components are added to the climate model to better represent our climate system
Climate Model:
Equations believed to represent the physical, chemical, and biological processes governing the climate system for the scale of interest
It can answer “What If” questionsfor example, what would the climate be if CO2 is doubled?
what would the climate be if Greenland ice is all melt?what………………………..if Amazon forest is gone?what…………………………if SF bay area
population is doubled?
Three Ways to Use Remote Sensing for Climate Model
• Satellite observed parameters, for example, albedo, vegetation, cloud droplet size
• Study climate process/feedback
• Evaluate Model Outputs
Climate Model (per NASA Earth Observatory Glossary http://earthobservatory.nasa.gov/Library/glossary.php3?mode=alpha&seg=b&segend=d )
A quantitative way of representing the interactions of the atmosphere, oceans, land surface, and ice.
Models can range from relatively simple to quite comprehensive.
Definition
Model components
MODIS image for Chen Du, China –satellite provides high resolution information on land cover, temperature, albedo, vegetation, aerosol, etc
An application: Urbanization - the satellite view
Night Light of Tokyo
data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS)
Night Light of Paris
pictures made by U.S. Defense Meteorological Satellites Program (DMSP)
Importance of land surface skin temperature (Tskin)
Land Skin Temperature is a good indicator of the energy balance at the Earth’s surface and the so-called greenhouse effect because it is one of the key parameters in land-surface processes at local, regional as well as global scales [Jin and Dickinson 2002].
The skin temperature used in calculating heat fluxes and radiation:F↑ = εσTskin
4 Eq. (1)SH = CDHU(Taero-Ta) Eq. (2)LE =CDEU(qTskin*-qa) Eq. (3)
(1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0
We use NASA EOS and NCAR Climate Model to examine the urbanization effects, in particular,
urban pollution
urban heat island effect (UHI)
50km
Urban heat island effectDaytime Nighttime
50km 50km
MODIS
(Jin, Dickinson and Zhang. 2005, J. of Climate)
Table 1: MODIS land cover table
Land Cover Type (LC)
1 Evergreen Needleleaf Forest
2 Evergreen Broadleaf Forest
3 Deciduous Needleleaf Forest
4 Deciduous Broadleaf Forest
5 Mixed Forest
6 Closed Shrubland
7 Open Shrubland
8 Woody Savannas
9 Savannas
10 Grassland
11 Permanent Wetland
12 Croplands
13 Urban and Built-Up
14 Cropland/Narural Vegetation Mosaic
15 Snow and Ice
16 Barren or Sparsely Vegetated
MODIS Observation
Beijing
(Jin, Dickinson, et al. 2005)
MODIS Observed Global urban heat island effect
Comparison of skin temperaturefor urban and nearby forests
MODIS
Cities have higher Tskin
than forests
Urbanization changes surface albedo (MODIS)
(Jin, Dickinson, and Zhang 2005, J. of Climate)
Urbanization changes surface emissivity (MODIS)
Use MODIS observed surface properties into model
MODIS11_L2 Emissivity_BAND 32 over Houston regions
Note: emissivity is missing over Houston urban regions, but available from monthly regions
MODIS15_A2 Leaf Area Index (LAI) over Houston regions
Note: on daily product, LAI over Houston regions is missing, but available from monthly data
Physical Processes for UHI:
(1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0
On Urban system:
(1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0
All underlined terms are changed!
The Land Surface Energy Balance
Urban Aerosol Effects
•Change atmosphere conditions to form clouds and rainfall
•Change surface insolation -> reduce urban surface temperature
Indirect Effect: serve as CCN
Cloud dropRain dropIce crystalIce precipitation
Aerosol Direct Effect: Scattering
0oC
surface
Aerosol reduce surface insolation
Aerosol Distributions over Land and Ocean have evident differences
July 2005
Satellite observations
NASA Aeronet Sites
http://aeronet.gsfc.nasa.gov/Ames has on of this site!
Aerosol effect on UHI
AERONET, New York EPA
Scale, Scale, Scale!! Jin, Shepherd, King 2005 JGR
Total solar radiation decreased by aerosol= 20Wm-2
(Jin, Shepherd, and King, 2005, JGR)
Aerosol decreases surface insolation
Based on M-D. Chou’s radiative transfer model
4.3
Jin and Shepherd, 2008, JGR
Urban system vs rainfall
• “Cities impact rainfall and can create their own rain and storms,” Marshall Shepherd explains.
• You need three basic ingredients for clouds and rainfall to develop, “
• air unstable - air lifting• CCN• moisture
Does urban have these?
Urban vs. Rainfall
• New Paper “The Impact Of Urbanization On Current And Future Coastal Precipitation: A Case Study For Houston” By Shepherd Et Al 2010
http://www.envplan.com/abstract.cgi?id=b34102t
Video
• http://www.met.sjsu.edu/metr112-videos/MET%20112%20Video%20Library-MP4/urban%20system/
Use satellite data to represent urban
Existing Coupled Land-Atmosphere Models:Coarse Resolution, Biogeophysics Focus
BARE SOIL: 15%
10%
GRASSLAND:50%
SHRUBS:
NEEDLELEAFTREES: 25%
e.g., CLM: (NCAR, DAO) NOAH: (NCEP)
Turbulence production
Urban thermal properties
Radiation trapping
Radiation attenuation
Canopy heating & cooling
Conceptual UMD-NASA CLM-Urban Model
Bare soilRoadBuilding roofs SuburbanHuman-grassOriginal treesUrban-water body
CLM original type:
Vegetation covered regions
Bare soil regions
CLM-urban model:
Surface type structure
water
Bare soil
Urban modifies: LAI, albedo, emisisivity, heat capacity, soil moisture, roughness length, etc
(Jin et al. 2006)
Physical Processes for UHI:
(1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0
On Urban system:
(1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0
All underlined terms are changed!
The Land Surface Energy Balance
CAM3/CLM3-Urban Model Results
Model results
Model results
Net longwave radiation
Model results
3 Km5/9/2011, 8 PM
MODIS land cover
WRF-urban
WRF 1km 5/5/20115 PM
6 PM, 5/5/2011
7 PM, 5/5/2011
5 PM, 5/6/2011
7 PM, 5/6/2011
9 PM, 5/6/2011
11 PM, 5/6/2011
1 AM, 5/7/2011
3 AM, 5/7/2011
5 AM, 5/7/2011
8 AM, 5/7/2011
10 AM, 5/7/2011
Evaluation of WRF-urban, MODIS
Class participation
• Why urban albedo is reduced?
• What is uncertainty of remotely sensed albedo over urban regions?
NASA “Mission to measurements”
Nadir UV/vis Satellite instruments
GOME-2• similar to GOME• launched 10.06• 80 x 40 km2 ground pixel• global coverage in 1.5 days
GOME
• 07.95 – 06.03 (full coverage)
• 4 channels 240 – 790 nm
• 0.2 – 04 nm FWHM
• nadir viewing
• 320 x 40 km2 ground pixel
• sun-synchronous orbit, 10:30
• global coverage in 3 days
SCIAMACHY
• 08.02 – today
• 8 channels 240 – 1700 nmand 2 – 2.4 μm
• 0.2 – 04 nm (1.5 nm) FWHM
• nadir viewing+ limb + solar / lunar occultation
• 60 x 30 km2 typical ground pixel
• sun-synchronous orbit, 10:00
• global coverage in 6 days
OMI• imaging spectrometer• launched 07.04• 13 x 24 -120 x 24 km2 ground pixel• global coverage in 1 day
Ozone Monitoring Instrument
• The NASA EOS Aura platform, launched on July 15, 2004, carries the Ozone Monitoring Instrument (OMI)
• Joint Dutch-Finnish Instrument with Duch/Finish/U.S. Science Team
• PI: P. Levelt, KNMI
• Hyperspectral wide FOV Radiometer
• 270-500 nm
• 13x24 km nadir footprint (highest resolution from space ! )
• Swath width 2600 km ( contiguous coverage )
• Radicals: Column O3, NO2, BrO, OClO
• O3 profile ~ 5-10 km vert resolution
• Tracers: Column SO2 , HCHO
• Aerosols (smoke, dust and sulfates)
• Cloud top press., cloud coverage
• Surface UVB
• Tropospheric ozone
13 km
(~2 sec flight))2600 km
12 km/24 km (binned & co-added)
flight direction» 7 km/sec
viewing angle± 57 deg
2-dimensional CCDwavelength
~ 580 pixels~ 780 pixels
SO2 burdens increase over China
70% of China’s energy is derived from coal burning
SO2 emissions increased at a rate 35%/decade in 1979-2000. China’s sulfate aerosol loading has increased by 17%/decade in 1979-2000 [Massie, Torres and Smith 2004]
25.5 million tons of SO2 was emitted by Chinese factories in 2005 up 27% from 2000
OMI can observe SO2 emissions in the planetary boundary layer (PBL) over
China on a daily basis and is able to track individual pollution plumes outflow to Pacific
Average (2005-2006) SO2 burdens over
USA, Europe and China:
25.5 million tons of SO2 was emitted by Chinese factories in 2005
up 27% from 2000
East-Aire’05 experiment
OMI NO2 December 2006 Average
OMI NO2 Western US
OMI NO2 Western US + Cities
OMI NO2 Western US + Cities + Power Plants
OMI NO2 Eastern US
OMI NO2 Asia
Nasa's CO2 satellite crashes into Antarctic ocean
• Nasa's pioneering satellite, designed to map carbon dioxide concentrations, has crashed into the ocean near Antarctica after running into technical difficulties during launch 24 February 2009
Summary
• Urban System is an extreme land cover and land use example
• Satellite can provide a set of key parameters for urban system
• Satellite data can be used to• Detect urban features
• Improve urban parameter/parameterization in a land surface model, which shall elad to better ability to simulate/predict weather and climate of urban regions
