Author: Travis Swaim

As a means of exploring additional avenues for Center Outreach, Live-Streaming and recording tests of ESSIC seminars will be conducted this week.  ESSIC will beta-test an evaluation unit provided by “NCast,” that is capable of both recording and streaming presentation and meeting content.   Monday’s seminar (5/14) will feature Dr. Edward Kim from NASA Goddard Space Flight Center. Thursday’s seminar (5/17) will feature two speakers, with talks scheduled to begin at 10:30am and 12:00pm …

This year’s AOGS-AGU (WPGM) Joint Assembly will be held at the Resorts World Sentosa (RWS) in Singapore from August 13-17.

Not only is it one of the biggest science conferences in Asia, but ESSIC’s own Professor Raghu Murtugudde was recently chosen as a distinguished lecturer for this year’s event.

Murtugudde is specifically scheduled to speak at the Ocean Sciences section of the conference on Thursday, August 16.

Murtugudde said he has been to the conference previously and said he even gave …

301 – Joint Center for Satellite Data Assimilation
Principal Investigator(s): Lars Peter Riishojgaard

The Joint Center for Satellite Data Assimilation is a US interagency distributed center charged with coordinating satellite data assimilation activities for environmental prediction applications between NASA, NOAA and the Department of Defense. The Director reports to a Management Oversight Board that consists of representatives from the three partner agencies, and he is responsible for the strategic direction and the daily execution of the research and development work undertaken by the Center as well as for representing the Center in national and international scientific contexts. The Fiscal Year 2011 budget of the Center amounted to ~$20M.

253 – Summary of Tropical Rainfall Measuring Mission (TRMM) Accomplishments to Date
Principal Investigator(s): Jian-Jian Wang

The Tropical Rainfall Measuring Mission (TRMM) is a joint project between NASA and the Japanese space agency, JAXA. It was launched on November 27, 1997 and continues to provide the research and operational communities unique precipitation information from space well into 2011. The first-time use of both active and passive microwave instruments and the precessing, low inclination orbit (35°) make TRMM the world’s foremost satellite for the study of precipitation and associated storms and climate processes in the tropics. To prepare for the TRMM Senior Review Proposal 2011, a thorough review of scientific accomplishment by TRMM is required.

252 – Improving AOD retrieval over ocean from MODIS
Principal Investigator(s): Jaehwa Lee

Aerosols exert a significant impact on climate change and air quality. These small airborne particles regulate the radiation budget through their direct and indirect effects (IPCC, 2007), or more specifically, by scattering and absorbing radiation and by modifying the microphysics of clouds. In the sense that aerosol shows highly variable spatial and temporal properties, the observations made from satellite, such as Moderate Resolution Spectroradiometer (MODIS) aboard the Terra and Aqua satellites, provide an unprecedented opportunity to investigate aerosol properties (AOP). However, a recent validation by Remer et al. (2008) showed underestimation of aerosol optical depth (AOD) over the ocean from Aqua-MODIS for high AOD case in particular. To resolve this issue, this study aims to improve AOD accuracy using new aerosol models archived by integrating Aerosol Robotic Network (AERONET) inversion data (Dubovik and King, 2000; Dubovik et al., 2006) and a tri-axial ellipsoidal dust database data (Meng et al., 2010).

251 – NASA GEOS-5 Chemistry Climate Model (CCM)
Principal Investigator(s): Elena Yegorova

Methane’s concentration has more than doubled since pre-industrial times, but its observed growth rate has declined since 1980 and has remained near zero during much of the 2000s. The causes of the observed growth rate are not well understood. It is important to improve understanding of methane’s behavior because a) methane is the third most important greenhouse gas after water vapor and CO2, with 25 times more global warming potential than CO2 on a 100 year time scale, b) methane contributes to the formation of tropospheric ozone, which is harmful to human health, and c) methane is part of the nonlinear methane (CH4)-carbon monoxide (CO)-hydroxyl radial (OH) system which largely controls the oxidizing capacity of the atmosphere. I am working on improving understanding of the observed variability of methane since 1980, using a computationally-efficient version of the NASA GEOS chemistry-climate model (GEOS CCM). The model accounts for the non-linear response to perturbations of the CH4-CO-OH system. The objective of this project is to understand the 1) sensitivity of methane to variations in OH and emissions and 2) causes of variability in observed methane, so as to lend confidence to projections of future methane growth.

250 – Integration of FEWS-NET into the Land Information System
Principal Investigator(s): B. Wind

A USGS famine early warning system (FEWS-NET) drought model, Water Requirement Satisfaction Index (WRSI), stood to benefit from being integrated into NASA (Code 614.3) ‘s Land Information System (LIS), which is a software framework for high performance land surface modeling and data assimilation. LIS brings to bear a host of flexible modeling and computing capabilities for those models privileged enough to be integrated into the LIS framework. However, LIS is a general-purpose Fortran (LINUX/UNIX) batch-queue submission shell executable. Whereas, USGS’s most up-to-the-minute implementation of WRSI was a custom Visual Basic .Net (Windows) graphical user interactive (GUI) application. A phased conversion and integration process was required.

248 – Modified Tau-Omega Model for Moderately to Densely Vegetated Landscapes
Principal Investigator(s): M. Kurum

Soil moisture (SM) is recognized as an important component of the water, energy, and carbon cycles at the interface between the Earth’s surface and atmosphere, yet it is difficult to measure globally using traditional in situ techniques. Several planned microwave space missions, most notably ESA’s Soil Moisture Ocean Salinity (SMOS) mission (launched November 2009) and NASA’s Soil Moisture Active Passive (SMAP) mission (to be launched 2014/2015), are focusing on obtaining accurate SM information over as much of the Earth’s land surface as possible. However, current baseline retrieval algorithms for SMOS and candidate retrieval algorithms for SMAP are based on an easily implemented but theoretically simple zero-order radiative transfer (RT) approach which includes components from the soil and vegetation, but ignores vegetation scattering except for the effect of the scatterers in the attenuation of the emission through the vegetation canopy. This approach essentially places a limit on the density of the vegetation through which SM can be accurately retrieved. Our proposed work involves the development of a new SM retrieval model which could potentially overcome this limitation and thus could be used with SMAP and SMOS data to increase the accuracy and reliability of SM products over moderately to densely vegetated landscapes.

Both SMOS and SMAP have mission requirements to retrieve SM to an accuracy of 0.04 cm3/cm3 through vegetation water content (VWC) of 5 kg/m2. These missions are expected to meet their requirement for SM retrieval accuracy using the heritage tau-omega model (zero-order RT solution) approach over approximately 65 % of the Earth’s land surface where the VWC does not exceed 5 kg/m2. As the density of vegetation increases, sensitivity to the underlying SM begins to degrade significantly and errors in the retrieved SM increase accordingly. Thus, knowledge of L-band vegetation features appears to be of great importance when the tau-omega approach is applied to dense vegetation (i.e. forest, mature corn, etc.) where scattering from branches and trunks (or stalks in the case of corn) is likely to be very important.

Our proposed new model is a first-order scattering RT model for microwave radiometry of vegetation at L-band. The model is based on an iterative solution (successive order of scattering) of the RT equations up to the first-order. This formulation adds a new scattering term to the tau-omega model. The additional term represents emission by particles in the vegetation layer and emission by the ground that is scattered once by particles in the layer. The resulting model represents an improvement over the standard zero-order solution since it accounts for the scattered vegetation and ground radiation that can have a pronounced effect on the observed emissivity and subsequent SM retrieval. Although the new approach would add another parameter to the list of unknowns in the inversion procedure to retrieve SM from microwave measurements, it has the advantage that the formula relating SM is physically-based, and as a result, should be more robust under varying conditions.