Temperature and Water Vapor Variance Scaling in Global Models: Comparisons to Satellite and Aircraft Data

• Published in: Journal of the atmospheric sciences 2011-09, Vol.68 (9), p.2156-2168
• Main Authors: KAHN, B. H, TEIXEIRA, J, ZHAO, M, FETZER, E. J, GETTELMAN, A, HRISTOVA-VELEVA, S. M, HUANG, X, KOCHANSKI, A. K, KÖHLER, M, KRUEGER, S. K, WOOD, R
• Format: Article
• Language: English
• Subjects: Aircraft; Benchmarks; Climate models; Earth, ocean, space; Exact sciences and technology; External geophysics; Marine; Meteorology; Physics of the high neutral atmosphere; Probability distribution; Science; Variables; Water vapor; Weather forecasting
• ISSN: 0022-4928; 1520-0469
• DOI: 10.1175/2011JAS3737.1

Observations of the scale dependence of height-resolved temperature T and water vapor q variability are valuable for improved subgrid-scale climate model parameterizations and model evaluation. Variance spectral benchmarks for T and q obtained from the Atmospheric Infrared Sounder (AIRS) are compared to those generated by state-of-the-art numerical weather prediction “analyses” and “free-running” climate model simulations with spatial resolution comparable to AIRS. The T and q spectra from both types of models are generally too steep, with small-scale variance up to several factors smaller than AIRS. However, the two model analyses more closely resemble AIRS than the two free-running model simulations. Scaling exponents obtained for AIRS column water vapor (CWV) and height-resolved layers of q are also compared to the superparameterized Community Atmospheric Model (SP-CAM), highlighting large differences in the magnitude of CWV variance and the relative flatness of height-resolved q scaling in SP-CAM. Height-resolved q spectra obtained from aircraft observations during the Variability of the American Monsoon Systems Ocean–Cloud–Atmosphere–Land Study Regional Experiment (VOCALS-REx) demonstrate changes in scaling exponents that depend on the observations’ proximity to the base of the subsidence inversion with scale breaks that occur at approximately the dominant cloud scale (~10–30 km). This suggests that finer spatial resolution requirements must be considered for future satellite observations of T and q than those currently planned for infrared and microwave satellite sounders.