Current issues with the CloudSat 2B-CWC-RVOD product http://www.cloudsat.cira.colostate.edu/dataIssues.php?prodid=76 2011-09-22T01:48:54+01:00 text/html 2011-09-22T01:48:54+01:00 http://cloudsat.cira.colostate.edu CloudSat DPC http://www.cloudsat.cira.colostate.edu/dataIssue.php?prodid=76&pvid=227&anomalyid=325230 The 2B-CWC-RVOD algorithm estimates liquid cloud properties using a radar forward model which includes the effects of attenuation by liquid cloud droplets. An error related to the calculation of the attenuation has been identified in the forward model. Due to a sign error, values for the two-way transmission in the forward model may be larger than 1.0. As a result, the forward-modeled attenuated reflectivity values can be larger than the unattenuated values.<br /> <br /> An evaluation shows that effective radii and liquid water contents are typically underestimated by the retrieval as a result of the forward model error. These effects are most pronounced for those profiles containing dBZe > -15 (i.e., those profiles which likely contain precipitation).<br /> <br /> This forward model is also used in the 2B-CWC-RO algorithm. The forward model is being corrected as part of the R05 product release. Note that this issue does not affect retrieved ice cloud properties.<br /><br /><a href="http://www.cloudsat.cira.colostate.edu/dataIssue.php?prodid=76&pvid=227&anomalyid=325230">(0 comments)</a><br /><br />Planned resolution: TBD text/html 2009-03-24T19:18:31+01:00 http://cloudsat.cira.colostate.edu CloudSat DPC http://www.cloudsat.cira.colostate.edu/dataIssue.php?prodid=76&pvid=227&anomalyid=315600 The 2B-CWC-RVOD algorithm has separate retrievals for liquid and ice clouds; the current algorithm does not attempt to retrieve both solid and liquid microphysical properties simultaneously in the same cloud column. Instead, separate retrievals are performed assuming that the entire cloud column is liquid-only and ice-only, and the two sets of results are combined into a composite profile according to a simple temperature relation (since we do not have an independent source of phase information). Ice-phase results are used for cold temperatures, liquid-phase results for warm temperatures, and a linear combination of the two are used in an intermediate temperature range, yielding an approximate mixed-phase solution.<br /> <br /> Note that one consequence of this retrieval approach is that, for the case of ice cloud overlying lower liquid cloud, the liquid-phase retrieval most likely overestimates the amount of attenuation of the radar beam in the column above the liquid layers. Future versions of the algorithm will likely take more sophisticated approaches to handling cloud columns with multiple phases, and will address the attenuation issue.<br /> <br /> The composite profile variable names all begin with "RVOD_"; the separate liquid-only and ice-only retrieval variable names begin with "LO_RVOD_" and "IO_RVOD_", respectively.<br /><br /><a href="http://www.cloudsat.cira.colostate.edu/dataIssue.php?prodid=76&pvid=227&anomalyid=315600">(0 comments)</a><br /><br />Planned resolution: TBD