The quantification of source-sink distribution of atmospheric CO2 in a finer resolution
can become uncertain due to the CO2 transport model-observation data mismatches. In
case of the coarse resolution global model, the mismatch occurs mainly due to unresolved
sub-grid scale processes, improper representation of the heterogeneity of surface fluxes
and model transport behaviour around the measurement site. So far, the high resolution
forward transport model simulations of CO2 at hourly to synoptic timescales have
attracted considerable interest. Therefore, we have simulated CO2 concentrations as non-
reactive trace gas over the Far East Asian region using the regional model WRF-CO2
developed at Jadavpur University, India and RIGC/JAMSTEC, Japan having realistic
meteorology as an integral part of the system and has successfully relaxed the limitation
in model horizontal resolution. Such a modeling system also accounts for the
heterogeneity in the surface fluxes. Using the WRF-CO2 model we have (i) investigated
spatio-temporal scale variation of CO2 concentration with observed data, and carried out
model inter-comparison with available data from TransCom3 models, (ii) carried out case
studies to evaluate performance of the model for synoptic variation of CO2 concentration
and meteorology, (iii) evaluated model performance for simulating the vertical profile of
CO2 in a tall tower. Results of our study show significant improvement of CO2 transport
simulation for the regional models due to increment of horizontal resolution in finer
scale. Higher resolution a priori fossil flux produces better concentration than the coarser
resolution flux. Temporal variabilities of CO2 at different observation stations are well
captured by the model. Particular case studies of CO2 transport during extreme weather
conditions have also revealed that the model performs well. Overall, the WRF-CO2
model is found to perform better than global models in terms of CO2 transport.
However, the WRF-CO2 model needs to be further evaluated over different regions of the
world. Hence, the present work can be extended using recent observational data acquired
by the AIRES, Nainital and aircraft measurement of vertical profile over New Delhi by
the Japan Airlines CONTRAIL programme with collaboration from JAMSTEC, and
other existing ground based and tall tower data in the South Asia region. Although
(Kumar and Naja et al. 2012, GMD) have evaluated WRF-Chem for several other
chemical species (CO, O3 and NOx), no high resolution chemistry modeling of CO2
transport has been attempted for the south Asia region. Therefore, this project of the
WRF-CO2 modelling for the Himalayan region along with central Indian region would be
a first time application of a very high resolution CO2 modelling over India. Furthermore,
the current work should be extended to understand temporal variations of long-lived CO2
in our geographical locations. The propose project is envisaged to provide the first time
high-resolution CO2 dynamic studies over South Asia. Concentration and flux values of
CO2 that will be obtained from the model simulation