Liu, Junjie: JPL (Project Lead)
Project Funding:
2011 - 2014
NRA: 2009 NASA: The Science of Terra and Aqua
Funded by NASA
Abstract:
The goal of the proposed work is to: 1) develop an Integrated Carbon Cycle Data Assimilation (ICCDA) framework; 2) quantify contemporaneous total surface carbon flux at model grid resolution (2.5ºx1.9º) and their uncertainty consistent with atmospheric, terrestrial dynamics and observations based on the available AIRS, GOSAT, and surface flask CO2; 3) improve the representation and uncertainty estimation of terrestrial carbon processes in a coupled carbon-climate model by assimilating LAI/fPAR from MODIS.
The ICCDA system is composed of a carbon-climate model and an Ensemble Kalman filter (EnKF). In this system, CO2 observations from AIRS, GOSAT, and surface flask CO2 observations will be assimilated simultaneously with contemporary meteorological CO2 observations to obtain surface carbon flux. The pivotal parameters relevant to carbon flux will be constrained by MODIS LAI/fPAR products, so that to improve terrestrial carbon processes and terrestrial carbon flux estimation.
The ICCDA system we propose has five distinct features: 1) The meteorological states are estimated along with CO2 concentration, surface carbon flux and parameters related to terrestrial carbon flux forecast; 2) The impact of the uncertainties in meteorological fields on CO2 forecast is fully considered by using ensemble meteorological analysis states to drive CO2 transport; 3) The parameters relevant to terrestrial carbon flux forecast are estimated within an interactive-coupled Atmosphere-Land-Biosphere model; 4) CO2 observations from multiple satellite sensors in addition to conventional CO2 observations are assimilated at the same time; 5) The surface carbon flux is dynamically evolved with time in the data assimilation system.
The analysis will focus on tropical region, since where satellite observations would make more significant impact due to the even sparser conventional observations compared to the other regions, and the bigger uncertainty of the carbon flux estimation in that region.
The assimilation of CO2 observations from AIRS and GOSAT, MODIS LAI/fPAR product and meteorological observations in the proposed ICCDA system will help answer the following scientific questions: 1) What is the spatial distribution of contemporary surface carbon flux? 2) Is the tropical region carbon source or sink? 3) What is the mean and uncertainty of the terrestrial carbon flux? 4) What is the impact of the uncertainty in meteorological fields on the carbon flux estimation and carbon flux forecast? 5) What observations are most helpful in constraining carbon flux and parameters relevant to carbon flux forecast?
The ongoing work of AIRS CO2 data assimilation on a coupled carbon-climate model and simulated experiments on a simple dynamical model has paved the way for this proposal.
2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- Estimating the Impacts of Recent Severe Amazonia Droughts on Forest Carbon Dynamics and Fluxes from Assimilating Satellite Observations in NCAR CESM with Ensemble Kalman Filter
-- (Junjie Liu, Sassan Saatchi, Yifan Yu, Kevin W Bowman, Meemong Lee)
[abstract]
2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)
- Constraining tropical biosphere CO2 fluxes by simultaneous assimilation of GOSAT Xco2 and AIRS mid-troposphere CO2 observations with variational inversion: a theoretical study
-- (Junjie Liu, Kevin W Bowman, Meemong Lee, Daven Henze, Edward Olsen)
[abstract]
2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- Estimation of surface carbon fluxes with an advanced data assimilation methodology
-- (Ji-Sun Kang, Eugenia Kalnay, Takemasa Miyoshi, Junjie Liu, Fung Inez)
[abstract]
- Quantification of the relationship between uncertainties in carbon cycle prediction and uncertainties in climate variables
-- (Junjie Liu, Inez Fung, Eugenia Kalnay, Ji-Sun Kang, Kevin W Bowman)
[abstract]
More details may be found in the following project profile(s):
