Cirrus Cloud Properties and the Large-Scale Meteorological Environment: Relationships Derived from A-Train and NCEP–NCAR Reanalysis Data

Abstract

Empirical knowledge of how cirrus cloud properties are coupled with the large-scale meteorological environment is a prerequisite for understanding the role of microphysical processes in the life cycle of cirrus cloud systems. Using active and passive remote sensing data from the A-Train, relationships between cirrus cloud properties and the large-scale dynamics are examined. Mesoscale cirrus events from along the A-Train track from 1 yr of data are sorted on the basis of vertical distributions of radar reflectivity and on large-scale meteorological parameters derived from the NCEP-NCAR reanalysis using a K-means cluster-analysis algorithm. With these defined regimes, the authors examine two questions: Given a cirrus cloud type defined by cloud properties, what are the large-scale dynamics? Vice versa, what cirrus cloud properties tend to emerge from large-scale dynamics regimes that tend to form cirrus? From the answers to these questions, the links between the large-scale dynamics regimes and the genre of cirrus that evolve within these regimes are identified. It is found that, to a considerable extent, the large-scale environment determines the bulk cirrus properties and that, within the dynamics regimes, cirrus cloud systems tend to evolve through life cycles, the details of which are not necessarily explained by the large-scale motions alone. These results suggest that, while simple relationships may be used to parameterize the gross properties of cirrus, more sophisticated parameterizations are required for representing the detailed structure and radiative feedbacks of these clouds.

Characterizing relative humidity with respect to ice in midlatitude cirrus clouds as a function of atmospheric state

“…We suspect that the lower frequency of cirrus in the winter, relative to the summer, is because more atmospheric states characterizing the winter have dynamical regimes unfavorable for new cirrus cloud development (i.e., anticyclone and northerly classes). Overall, our results support previous studies such as Mace et al [2006], Berry and Mace [2013] and others showing that large-scale dynamical regimes are most important to explaining variability in cirrus cloud macrophysical and microphysical properties.…”

“…Overall, our results support previous studies such as Mace et al . [], Berry and Mace [] and others showing that large‐scale dynamical regimes are most important to explaining variability in cirrus cloud macrophysical and microphysical properties.…”

Cirrus Clouds and Their Response to Anthropogenic Activities

“…Advanced satellite remote sensing capabilities create new opportunities for assessing and synthesizing findings from such measurements for model development and evaluation of (optically thin) cirrus clouds [101,102]. Combining remote sensing information with reanalysis data allows connections to be made between bulk cirrus cloud properties and the large-scale dynamical regimes in which anvil cirrus form and evolve [103]. Due to the link between of convective detrainment and anvil cirrus formation, it is necessary to improve parameterizations of deep convection used in GCMs, especially regarding frequency, location, and strength of upper tropospheric mass fluxes and their link to detrainment of frozen condensate [104,105].…”

Midlatitude Cirrus Clouds at the SACOL Site: Macrophysical Properties and Large‐Scale Atmospheric States

“…In order to better understand how large-scale atmospheric conditions affect cirrus characteristics, cirrus events are further grouped into four distinct cloud regimes based on the clustering analysis. This method is proved to be an effective way to understand the connections between cloud properties and synoptic processes (Berry & Mace, 2013;Gordon & Norris, 2010;Jakob & Tselioudis, 2003;Zhang et al, 2007).…”