DYCOMS Overview

Bjorn Stevens ... dycoms-ii*
overview | articles | facilities | data | links

The Second Dynamics and Chemistry of Marine Stratocumulus field study (DYCOMS-II) was specifically designed to provide:

a suite of test cases for subsequent simulation;
tests of LES derived entrainment parameterizations.

Secondary objectives included:

testing a new technique to measure large-scale divergence;
increasing our understanding of the diurnal cycle;
quantifying precipitation and its effect on cloud structure;
evaluating aerosol effects on precipitation and clouds.

The program consisted of nine flights, WSW of Los Angeles, CA, in the heart of the stratocumulus region of the NE Pacific. The target area for the flights is shown by the shaded box above. During DYCOMS-II seven of the nine flights were nocturnal, whereas day and night time flights from previous campaigns are shown by the open and closed circles on the figure above. [Papers].

Measurements from the first research flight were used to provide some of the most definitive constraints on theories of cloud top entrainment, as well as stringent test cases of both LES and single column models. [Papers | GCSS RF01]

A surprise, consistent with less than expected entrainment, was more than expected drizzle. Flight averaged drizzle rates frequently approached 1 mm/day and locally were much larger. Drizzle also tended to be associated with the development of open cellular structure as shown in the satellite imagery and radar reflectivity on the right. These were termed pockets of open cells, or POCS, by DYCOMS investigators. [Papers]

*This material is based in part upon work supported by the National Science Foundation under award number ATM-0097053. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


		Bjorn Stevens ... dycoms-ii*		*overview* \| articles \| facilities \| data \| links
			The Second Dynamics and Chemistry of Marine Stratocumulus field study (DYCOMS-II) was specifically designed to provide: a suite of test cases for subsequent simulation; tests of LES derived entrainment parameterizations. Secondary objectives included: testing a new technique to measure large-scale divergence; increasing our understanding of the diurnal cycle; quantifying precipitation and its effect on cloud structure; evaluating aerosol effects on precipitation and clouds.
		The program consisted of nine flights, WSW of Los Angeles, CA, in the heart of the stratocumulus region of the NE Pacific. The target area for the flights is shown by the shaded box above. During DYCOMS-II seven of the nine flights were nocturnal, whereas day and night time flights from previous campaigns are shown by the open and closed circles on the figure above. [Papers].
					Measurements from the first research flight were used to provide some of the most definitive constraints on theories of cloud top entrainment, as well as stringent test cases of both LES and single column models. [Papers \| GCSS RF01]

	A surprise, consistent with less than expected entrainment, was more than expected drizzle. Flight averaged drizzle rates frequently approached 1 mm/day and locally were much larger. Drizzle also tended to be associated with the development of open cellular structure as shown in the satellite imagery and radar reflectivity on the right. These were termed pockets of open cells, or POCS, by DYCOMS investigators. [Papers]
*This material is based in part upon work supported by the National Science Foundation under award number ATM-0097053. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.