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Potential of using CO2 observations over India in a regional carbon budget estimation by improving the modelling system.

Authors :
Thilakan, Vishnu
Pillai, Dhanyalekshmi
Sukumaran, Jithin
Gerbig, Christoph
Hakkim, Haseeb
Sinha, Vinayak
Terao, Yukio
Naja, Manish
Deshpande, Monish Vijay
Source :
Atmospheric Chemistry & Physics; 2024, Vol. 24 Issue 9, p5315-5335, 21p
Publication Year :
2024

Abstract

Devising effective national-level climate action plans requires a more detailed understanding of the regional distribution of sources and sinks of greenhouse gases. Due to insufficient observations and modelling capabilities, India's current carbon source–sink estimates are uncertain. This study uses a high-resolution Lagrangian transport model to examine the potential of available CO 2 observations over India for inverse estimation of regional carbon fluxes. We use four different sites in India that vary in the measurement technique, frequency and spatial representation. These observations exhibit substantial seasonal (7.5 to 9.2 ppm) and intra-seasonal (2 to 12 ppm) variability. Our modelling framework, a high-resolution Weather Research and Forecasting Model combined with the Stochastic Time-Inverted Lagrangian Transport model (WRF–STILT), performs better in simulating seasonal (R2=0.50 to 0.96) and diurnal (R2=0.96) variability (for the Mohali station) of observed CO 2 than the current-generation global models (CarboScope, CarbonTracker and ECMWF EGG4). The seasonal CO 2 concentration variability in Mohali, associated with crop residue burning, is largely underestimated by the models. WRF–STILT captures the seasonal biospheric variability over Nainital better than the global models but underestimates the strength of the CO 2 uptake by crops. The choice of emission inventory in the modelling framework alone leads to significant biases in simulations (5 to 10 ppm), endorsing the need for accounting for emission fluxes, especially for non-background sites. Our study highlights the possibility of using the CO 2 observations from these Indian stations for deducing carbon flux information at regional (Nainital) and suburban to urban (Mohali, Shadnagar and Nagpur) scales with the help of a high-resolution model. On accounting for observed variability in CO 2 , the global carbon data assimilation system can benefit from the measurements from the Indian subcontinent. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
16807316
Volume :
24
Issue :
9
Database :
Complementary Index
Journal :
Atmospheric Chemistry & Physics
Publication Type :
Academic Journal
Accession number :
177435788
Full Text :
https://doi.org/10.5194/acp-24-5315-2024