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Menglin JinMenglin JinDepartment of Atmospheric & Oceanic ScienceDepartment of Atmospheric & Oceanic ScienceUniversity of Maryland, College parkUniversity of Maryland, College park
Observed Land Impacts on Observed Land Impacts on Clouds, Water Vapor, and Rainfall at Clouds, Water Vapor, and Rainfall at
Continental ScalesContinental Scales
Michael D. KingMichael D. KingEarth-Sun Exploration Division, Earth-Sun Exploration Division, NASA Goddard Space Flight Center, NASA Goddard Space Flight Center, Greenbelt, MarylandGreenbelt, Maryland
January5, 2006January5, 2006MODIS Science Team MeetingMODIS Science Team Meeting
How do the continents affect large-scale hydrological cycles?
How important can one continent be to the climate system?
1. Scientific Questions:
2. Data Sets Used:•5-years of NASA Terra MODIS observations; •3-year NASA Aqua MODIS observations;•TRMM observations;•Global Precipitation Climatology Project (GPCP); global precipitation analysis; •NCEP reanalysis;to assess the land impacts on clouds, rainfall, and water vapor at continental scales.
3. Why Continental Scale? - Importance of Continental Scale
• Features at continental scale is index of land impact on climate
• Continental scale is critical in testing the accuracy of GCM Coe, M.T. (2000, J. of Climate),
Jin, M. et al. (1997 J. of Climate)
• Few studies focus on continental scale
With knowledge of local/global features, can we extend to know the features at continental scale?
Answer: No, as climate system is nonlinear
Knowing other scales cannot ensure understanding at continental scale
Cloud Features at Various Spatial Scales
5 year averaged Cloud Optical Thickness
Land Impacts on Cloud Optical ThicknessLand Impacts on Cloud Optical Thickness
Continent Impacts on Cloud Optical Thickness
Probability Density FunctionProbability Density Function
land
ocean
Temporal Variations of PDF for Cloud Optical Thickness
MODIS Cloud Fraction Daytime
Ocean OnlyOcean Only (90°N-90°S, 180°E-180°W) (90°N-90°S, 180°E-180°W)
LandLandAverage 0.693 0.536
Ocean Land
Seasonal range 0.04 0.11
MODIS Cloud Fraction Daytime
MODIS Cloud Fraction Daytime
Ocean OnlyOcean Only
Land OnlyLand Only
MODIS Cloud Effective Radius
Ice clouds
Liquid water clouds
Cirrus FractionCirrus Fraction
Land enlarges seasonality of cirrus fractionLand enlarges seasonality of cirrus fraction
Column Water Vapor
Land enlarges seasonality, and reduces the absolute value of water vapor
MODIS Column Water VaporMODIS Column Water Vapor NCEP Reanalysis Water VaporNCEP Reanalysis Water Vapor
MODIS is valuable to evaluate Reanalysis and model simulationsMODIS is valuable to evaluate Reanalysis and model simulations
Probability Density FunctionProbability Density Function
Monthly rainfall forNorthern Hemisphere, North America,and Eurasia.
GPCP Data
Continents have larger rainfall seasonality
SummarySummary SummarySummary
• MODIS observations are extremely useful in understanding land MODIS observations are extremely useful in understanding land impacts on global climate. impacts on global climate.
• Land mass enhances seasonality of clouds, water vapor, and Land mass enhances seasonality of clouds, water vapor, and rainfall. rainfall.
• Land decreases the liquid cloud effective radius, cloud fraction, Land decreases the liquid cloud effective radius, cloud fraction, and water vapor.and water vapor.
• Need More Work on providing Need More Work on providing insightful statisticsinsightful statistics
physical interpretation physical interpretation