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METR202- Study Urban Climate System Using Satellite Remote Sensing and Climate Model

METR202- Study Urban Climate System Using Satellite Remote Sensing and Climate Model. Professor Menglin Jin San Jose State University. Outline: Key Urban Features Satellite Approach Model Approach Future Directions. We studied: Urban Heat Island Effect

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METR202- Study Urban Climate System Using Satellite Remote Sensing and Climate Model

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  1. METR202- Study Urban Climate System Using Satellite Remote Sensing and Climate Model Professor Menglin Jin San Jose State University Outline: Key Urban Features Satellite Approach Model Approach Future Directions

  2. We studied: Urban Heat Island Effect Urban aerosol effect on clouds and rainfall

  3. Why do we need to Study Urban regions? • Urban is an extremecase of human-change natural land cover. • Urban regions has strong pollution, greenhouse emission. • 60% people in USA live in cities • Urban has unique water and heat cycles what directly • affect human life

  4. Related Publications Jin, M, 2012; Development of UHI index. J. of Climate Jin, M., J. M. Shepherd, M. D. King, 2005: Urban aerosols and their interaction with clouds and rainfall: A case study for New York and Houston. J. Geophysical Research, 110, D10S20, doi:10.1029/2004JD005081. Jin, M, R. E. Dickinson, and D-L. Zhang, 2005: The footprint of urban areas on global climate as characterized by MODIS. Journal of Climate, vol. 18, No. 10, pages 1551-1565 Jin, M. and J. M. Shepherd, 2005: On including urban landscape in land surface model – How can satellite data help? Bull. AMS, vol 86, No. 5, 681-689. Jin, M. J. M. Shepherd, and Christa Peters-Lidard, 2007: Development of A Parameterization For Simulating the Urban Temperature Hazard Using Satellite Observations In Climate Modelin press by Natural Hazards. Jin, M. and M. J. Shepherd, 2007: Aerosol effects on clouds and rainfall: urban vs. ocean. Revised for JGR

  5. SF, 2008

  6. Urban Heat Island Effect (UHI) This phenomenon describes urban and suburban temperatures that are 2 to 10°F (1 to 6°C) hotter than nearby rural areas. UHI impacts: Elevated temperatures can impact communities by increasing peak energy demand, air conditioning costs, air pollution levels, and heat-related illness and mortality High temperature also enhances surface convection, and causes more clouds and rainfall

  7. Surface temperature Urban Heat Island Effect (UHI): Urban surface is hotter than that of surrounding non-urban regions We need to understand why and what are UHI effects

  8. Traditional Way to Measure Urban Surface Temperature

  9. UHI is function of city size, location, geographic conditions, population

  10. Video: Urban Heat Island Effect (UHI) http://www.met.sjsu.edu/metr112-videos/MET%20112%20Video%20Library-MP4/urban%20system/ Urban Heat Island.mp4 reasons for UHI how to reduce UHI

  11. Video: Urban Rainfall Effect http://www.met.sjsu.edu/metr112-videos/MET%20112%20Video%20Library-MP4/urban%20system / Urban Rainfall Effect.mp4

  12. 43% of Land Area Dominated by Agriculture % of Land Area Built-up 3 - 6%

  13. Our Research Approach • Using Satellite Remote Sensing to detect features of urban system • Using Climate Model (land surface model) to simulate UHI and aerosol effects

  14. Satellite observations retrieve urban system: Land surface properties: surface temperature, surface albedo, emissivity, soil moisture, vegetation cover Atmosphere conditions: aerosol, clouds, and rainfall It shows that urbanization significantly changes weather and climate

  15. 1. Satellite remote sensing on urban regions MODIS land cover Red color means urban built-up

  16. Night Light of Tokyo

  17. Night Light of Paris

  18. pictures made by U.S. Defense Meteorological Satellites Program (DMSP)

  19. Urbanization Effects Land Surface Energy Budget: (1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0 Dr. Menglin Jin San Jose State University

  20. Urbanization Effects Land Surface Energy Budget: (1-α)Sd +LWd-εσTskin4 +SH+LE + G= 0 Urbanization changes: Albedo (black surface) Vegetation ocverage (EP, roughness length) Sd, LWd (by aerosols, clouds) Tskin, SH/LE/G Dr. Menglin Jin San Jose State University

  21. Urbanization impacts on skin temperature 10°C !!! EOS MODIS observed monthly mean daytime shows evident urban heat island effect (Copied from Jin et al, 2005a). The red areas show the dense building regions of Beijing.

  22. Urbanization changes surface albedo (MODIS) Urban surface albedo has a 4-6% decrease -> more solar radiation will be absorbed at surface\ increase surface temperature

  23. Urbanization reduces surface emissivity (MODIS) (Jin et al. 2005, J. of Climate) Urban reduces surface emissivity -> Less longwave radiation emitted from surface  More heat is kept at surface Surface temperature increases

  24. 3. Urban Aerosols and Their Direct Effects on Clouds, Surface Insolation, and Surface Temperature

  25. Urban Pollution Sources Aerosols are solid/liquid particles pending in atmosphere Traffic Size -0.01-100μm Residence time – hours-days Industry Indoor warming

  26. Video • Urban aerosol effect on rainfall http://www.met.sjsu.edu/metr112-videos/MET%20112%20Video%20Library-MP4/urban%20system/ Summer Precip w-Pollution.mp4 Winter Precip w-Pollution.mp4

  27. NASA MODIS observed Aerosol Distribution July 2005

  28. 0oC Cloud drop Rain drop Ice crystal Ice precipitation Indirect Effect: serve as CCN Aerosol Direct Effect: Scattering Absorb surface Black carbon heats atmosphere and surface Most aerosols cool surface More aerosol ->small cloud effective radius-> high cloud albedo->cooling (Kaufmann and Koren 2006) More aerosol->reduce rainfall (Rosenfeld 2000)

  29. Aerosol decreases surface insolation Total solar radiation decreased by aerosol=20Wm-2 Based on NASA GMAO radiative transfer model (Jin, Shepherd, and King, 2005, JGR)

  30. 6-year averaged AERONET measurements Beijing New York City • 6-year daily averaged aerosol optical thickness (AOT) show • significant differences between Beijing and New York City • seasonal variation of urban aerosol

  31. Reduction of surface insolation, Beijing

  32. Urban Effects on Climate: An Analogue Urban Effects on Radiative Forcing Known, but Effects on Water Cycle Processes (e.g. Precipitation Variability) Less Understood (IPCC, 2007)

  33. Urban Heat Island Effect (UHI) Is it a • day time phenomenon only • night time phenomenon only • both day+night phenomenon How to deal with UHI? Watch video: http://www.youtube.com/watch?feature=endscreen&NR=1&v=t-sXHl3l-rM

  34. A case for San Jose-SF Bay Area, China

  35. 5/9/2011, 8 PM 3 Km

  36. WRF 1km 5/5/2011 5 PM

  37. 6 PM, 5/5/2011

  38. 7 PM, 5/5/2011

  39. 5 PM, 5/6/2011

  40. 7 PM, 5/6/2011

  41. 9 PM, 5/6/2011

  42. 11 PM, 5/6/2011

  43. 1 AM, 5/7/2011

  44. 3 AM, 5/7/2011

  45. 5 AM, 5/7/2011

  46. 8 AM, 5/7/2011

  47. 10 AM, 5/7/2011

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