CO 2 annual and semiannual cycles from multiple satellite retrievals and models

摘要

Satellite CO 2 retrievals from the Greenhouse gases Observing SATellite (GOSAT), Atmospheric Infrared Sounder (AIRS), and Tropospheric Emission Spectrometer (TES) and in situ measurements from the National Oceanic and Atmospheric Administration ?￠???? Earth System Research Laboratory (NOAA?￠????ESRL) Surface CO 2 and Total Carbon Column Observing Network (TCCON) are utilized to explore the CO 2 variability at different altitudes. A multiple regression method is used to calculate the CO 2 annual cycle and semiannual cycle amplitudes from different data sets. The CO 2 annual cycle and semiannual cycle amplitudes for GOSAT X CO2 and TCCON X CO2 are consistent but smaller than those seen in the NOAA?￠????ESRL surface data. The CO 2 annual and semiannual cycles are smallest in the AIRS midtropospheric CO 2 compared with other data sets in the Northern Hemisphere. The amplitudes for the CO 2 annual cycle and semiannual cycle from GOSAT, TES, and AIRS CO 2 are small and comparable to each other in the Southern Hemisphere. Similar regression analysis is applied to the Model for OZone And Related chemical Tracers?￠????2 and CarbonTracker model CO 2 . The convolved model CO 2 annual cycle and semiannual cycle amplitudes are similar to those from the satellite CO 2 retrievals, although the models tend to underestimate the CO 2 seasonal cycle amplitudes in the Northern Hemisphere midlatitudes and underestimate the CO 2 semiannual cycle amplitudes in the high latitudes. These results can be used to better understand the vertical structures for the CO 2 annual cycle and semiannual cycle and help identify deficiencies in the models, which are very important for the carbon budget study.