The influence of large-scale dynamical forcing and meteorological regime on Arctic cloud microphysical properties

Description

The objective of this work is to determine how the entire time series of cloud property and radiation measurement data from the NSA site (now well into its second decade) can be used to test and refine climate model parameterizations. This is particularly germane given recent attention to improving mixed-phase cloud representation in climate models. We determine the time periods in which the NSA site is under the influence of major meteorological regimes (e.g., Aleutian Low, Siberian High, Central Arctic/Beaufort Sea High) in two ways: (1) inspection of daily mean NCEP reanalysis data, and (2) k-means clustering on surface meteorological data from NSA itself. We then describe the cloud properties and their ranges for each of these significant regimes and for each season, as derived from ARSCL, MWR, SKYRAD, and other sensors. In this way, we create "ensembles" of test cases for cloud properties, physically relevant to actual meteorological states, that can be used to robustly test climate model parameterizations. This enables testing of the climate model parameterizations over the full range of meteorological variability found in nature and explained by large-scale dynamical forcing. We present this technique as a potentially valuable supplement to the more common method of testing climate model parameterizations against individual "case studies" from intensive aircraft field campaigns such as ISDAC and M-PACE.