Spectroscopic requirements for ACCURATE, a microwave and infrared-laser occultation satellite mission

TY - JOUR

T1 - Spectroscopic requirements for ACCURATE, a microwave and infrared-laser occultation satellite mission

AU - Harrison, J.J.

AU - Bernath, P.F.

AU - Kirchengast, G.

PY - 2011/9/1

Y1 - 2011/9/1

N2 - The proposed satellite mission ACCURATE consists of a small constellation of satellites in low Earth orbit, combining microwave occultation for thermodynamic state profiling with infrared-laser occultation for greenhouse gas and line-of-sight wind profiling. The mission aims to detect six greenhouse gas molecules with four additional isotopologues (H O, CO , CH , N O, O , CO, CO , OC O, HDO, and H O) in the upper troposphere and lower stratosphere in the 4000-5000cm spectral region. Greenhouse gas profiles will be retrieved to within 1-2% accuracy using a 'differential' method, requiring two spectral points for each species - one to sample the spectral line and the other nearby to sample the baseline.An estimation of retrieval errors for the ACCURATE mission reveals that errors in spectroscopic line parameters dominate all other error sources. Poor knowledge of the spectroscopy introduces systematic errors into the retrieved greenhouse gas profiles. Using a simple approach, it was shown that the best line parameters currently available are too large to allow retrievals of greenhouse gases to within the stated ACCURATE mission goals of 1% accuracy for CO and 2% for all other species. Therefore, spectroscopic line parameters for targeted lines need to be improved before the ACCURATE mission can be launched. Requirements have been formulated in this direction, and laboratory experiments outlined that could meet these requirements.

AB - The proposed satellite mission ACCURATE consists of a small constellation of satellites in low Earth orbit, combining microwave occultation for thermodynamic state profiling with infrared-laser occultation for greenhouse gas and line-of-sight wind profiling. The mission aims to detect six greenhouse gas molecules with four additional isotopologues (H O, CO , CH , N O, O , CO, CO , OC O, HDO, and H O) in the upper troposphere and lower stratosphere in the 4000-5000cm spectral region. Greenhouse gas profiles will be retrieved to within 1-2% accuracy using a 'differential' method, requiring two spectral points for each species - one to sample the spectral line and the other nearby to sample the baseline.An estimation of retrieval errors for the ACCURATE mission reveals that errors in spectroscopic line parameters dominate all other error sources. Poor knowledge of the spectroscopy introduces systematic errors into the retrieved greenhouse gas profiles. Using a simple approach, it was shown that the best line parameters currently available are too large to allow retrievals of greenhouse gases to within the stated ACCURATE mission goals of 1% accuracy for CO and 2% for all other species. Therefore, spectroscopic line parameters for targeted lines need to be improved before the ACCURATE mission can be launched. Requirements have been formulated in this direction, and laboratory experiments outlined that could meet these requirements.

UR - http://www.scopus.com/inward/record.url?scp=80051559209&partnerID=8YFLogxK

U2 - 10.1016/j.jqsrt.2011.06.003

DO - 10.1016/j.jqsrt.2011.06.003

M3 - Article

AN - SCOPUS:80051559209

SN - 0022-4073

VL - 112

SP - 2347

EP - 2354

JO - Journal of Quantitative Spectroscopy and Radiative Transfer

JF - Journal of Quantitative Spectroscopy and Radiative Transfer

IS - 14

ER -