Investigation of Atmospheric Recycling Rate from Observation and Model James Trammell 1 , Xun Jiang 1 , Liming Li 2 , Maochang Liang 3 , Jing Zhou 4 , and Yuk L. Yung 5 1 Department of Earth & Atmospheric Sciences, Univ. of Houston 2 Department of Physics, Univ. of Houston 3 Research Center for Environmental Changes, Academia Sinica 4 Department of Physics, Beijing Normal University 5 Division of Geological & Planetary Sciences, Caltech AGU Fall Meeting, Dec 3, 2012
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1 Department of Earth & Atmospheric Sciences, Univ. of Houston
Investigation of Atmospheric Recycling Rate from Observation and Model James Trammell 1 , Xun Jiang 1 , Liming Li 2 , Maochang Liang 3 , Jing Zhou 4 , and Yuk L. Yung 5. 1 Department of Earth & Atmospheric Sciences, Univ. of Houston 2 Department of Physics, Univ. of Houston - PowerPoint PPT Presentation
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Investigation of Atmospheric Recycling Rate from Observation and Model
James Trammell1, Xun Jiang1, Liming Li2, Maochang Liang3, Jing Zhou4, and Yuk L. Yung5
1 Department of Earth & Atmospheric Sciences, Univ. of Houston
2Department of Physics, Univ. of Houston
3 Research Center for Environmental Changes, Academia Sinica
4Department of Physics, Beijing Normal University
5 Division of Geological & Planetary Sciences, Caltech
AGU Fall Meeting, Dec 3, 2012
Overview
• Motivation
• Data
• Observational Study
• GISS Model Results • Conclusions
Motivation• To understand the hydrological cycle as a response to
global warming
• To quantitatively simulate the precipitation trend in order to predict the variation of precipitation in the future
• To better understand the physics behind the temporal variation and spatial pattern of precipitation
• To alleviate, forecast, and prepare for the consequences of drought in one area and flooding in another
Data
I. Water VaporSpecial Sensor Microwave/Imager (SSM/I) (V6)
Spatial: 0.25º× 0.25º; Temporal: 1988-present
II. Precipitation1. Global Precipitation Climatology Project (GPCP) (V2.1)
GISS ComparisonDeseasonalized / Lowpass Filtered Column Water
Historic Run Control Run (fixed)
1.12 ± 0.17 mm/decade
0.55 ± 0.09 mm/decade
0.03 ± 0.12 mm/decade
-0.01 ± 0.08 mm/decade
Conclusions- Observations and GISS historic run
- Recycling rate has increased in the ITCZ and decreased in the neighboring regions over the past two decades- Temporal variation is stronger in precipitation than in water vapor, which results to the positive (negative) trend of recycling rate in the high (low) precipitation region - GISS model captures the observed precipitation, water vapor, and recycling rate trends qualitatively
- Historic and control run comparison- suggests that the increasing greenhouse gas forcing affects the temporal variation of precipitation, contributing to precipitation extremes
Acknowledgments
• NASA ROSES-2010 NEWS grant NNX13AC04G
• Eric J Fetzer (JPL), Moustafa T Chahine (JPL), Edward T Olsen (JPL), Luke Chen (JPL)
Thank You!!
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Spatial Pattern of the Mean Precipitation for 1988-2008
Ensemble Runs
- 5 different colors represent 5 different initial conditions, all with the historic run forcing