PP003-0011
Variability of Amazon water balance determined by atmospheric isotopic water vapor measurements

Monday, 7 December 2020
Poster
Mingjie Shi1, John R Worden2, Adriana Bailey, David Noone4, Camille Risi5, Rong Fu6, Sarah R Worden7, Robert L Herman8, Vivienne Payne9, Thomas S Pagano10, Kevin W Bowman2, A. Anthony Bloom2, Sassan Saatchi11, Junjie Liu2, Michael Keller12 and Joshua Fisher2, (1)University of California at Los Angeles, Joint Institute for Regional Earth System Science and Engineering, Los Angeles, CA, United States, (2)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (3)University of Auckland, Department of Physics, Auckland, New Zealand, (4)CNRS, Laboratoire de Météorologie Dynamique, Paris, France, (5)University of California, Los Angeles, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA, United States, (6)University of California, Los Angeles, Physics, Los Angeles, CA, United States, (7)JPL, Pasadena, CA, United States, (8)NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (9)Jet Propulsion Laboratory, Pasadena, CA, United States, (10)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (11)USDA Forest Service, International Institute of Tropical Forestry, Rio Piedras, PR, United States
Abstract:
Water budgets in terrestrial ecosystems are closely related to evapotranspiration (ET) and precipitation. ET and precipitation can be inferred through remote sensing, but have large uncertainties associated with cloud cover, rain amount, or uncertainties and biases of re-analysis data; thus, quantifying regional ET and precipitation is still a challenge. It was demonstrated that satellite observations of isotopic composition of atmospheric water vapor normalized to a reference value of 0.004 m3 m-3 (herein dD_004) can quantify the spatiotemporal variability of ET minus precipitation (ET-P) over the tropical oceans. We use the atmospheric deuterium measurements from Atmospheric Infrared Sounder (AIRS), multiple ET products from satellite and re-analysis, and a variety of precipitation products. We show that the deuterium proxy dD_004 can be used to quantify seasonal variability of ET-P over the sub-basins of Amazonia. In addition, the isotope-enabled Community Atmospheric Model (herein ICAM), which includes isotopic physics routines, also shows the expected linearity between ET-P and the deuterium proxy dD_004 over the Amazon. In addition, we quantify the variability of different ET-P calculations, and demonstrate that ET-P estimations based on dD_004 are not fundamentally different than ET-P calculated with varied ET and precipitation products. Thus, dD_004 can be used as an ET-P proxy over Amazon or other tropical continents. These data and method represent a new and revealing view into the moisture balance of terrestrial hydrology over the tropics.
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