Thin Liquid Water Clouds: Their Importance and Our Challenge Export

@article{TurnerEtAl2007ThinClouds, abstract = {Many of the clouds important to the Earth's energy balance, from the Tropics to the Arctic, contain small amounts of liquid water. Longwave and shortwave radiative fluxes are very sensitive to small perturbations of the cloud liquid water path (LWP), when the LWP is small (i.e., < 100 g m−2; clouds with LWP less than this threshold will be referred to as ” thin”). Thus, the radiative properties of these thin liquid water clouds must be well understood to capture them correctly in climate models. We review the importance of these thin clouds to the Earth's energy balance, and explain the difficulties in observing them. In particular, because these clouds are thin, potentially mixed phase, and often broken (i.e., have large 3D variability), it is challenging to retrieve their microphysical properties accurately. We describe a retrieval algorithm intercomparison that was conducted to evaluate the issues involved. The intercomparison used data collected at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site and included 18 different algorithms to evaluate their retrieved LWP, optical depth, and effective radii. Surprisingly, evaluation of the simplest case, a single-layer overcast stratocumulus, revealed that huge discrepancies exist among the various techniques, even among different algorithms that are in the same general classification. This suggests that, despite considerable advances that have occurred in the field, much more work must be done, and we discuss potential avenues for future research.)}, author = {Turner, D. D. and Vogelmann, A. M. and Austin, R. T. and Barnard, J. C. and Cady-Pereira, K. and Chiu, J. C. and Clough, S. A. and Flynn, C. and Khaiyer, M. M. and Liljegren, J. and Johnson, K. and Lin, B. and Long, C. and Marshak, A. and Matrosov, S. Y. and Mcfarlane, S. A. and Miller, M. and Min, Q. and Minnis, P. and O'Hirok, W. and Wang, Z. and Wiscombe, W.}, citeulike-article-id = {1602513}, journal = {Bulletin of the American Meteorological Society}, keywords = {boundarylayer, clouds, clouds-low, remotesensing}, month = {February}, number = {2}, pages = {177--190}, posted-at = {2007-08-29 02:32:26}, priority = {0}, title = {Thin Liquid Water Clouds: Their Importance and Our Challenge}, volume = {88}, year = {2007} }

TY - JOUR ID - TurnerEtAl2007ThinClouds L3 - citeulike-article-id:1602513 N2 - Many of the clouds important to the Earth's energy balance, from the Tropics to the Arctic, contain small amounts of liquid water. Longwave and shortwave radiative fluxes are very sensitive to small perturbations of the cloud liquid water path (LWP), when the LWP is small (i.e., < 100 g m−2; clouds with LWP less than this threshold will be referred to as “thin”). Thus, the radiative properties of these thin liquid water clouds must be well understood to capture them correctly in climate models. We review the importance of these thin clouds to the Earth's energy balance, and explain the difficulties in observing them. In particular, because these clouds are thin, potentially mixed phase, and often broken (i.e., have large 3D variability), it is challenging to retrieve their microphysical properties accurately. We describe a retrieval algorithm intercomparison that was conducted to evaluate the issues involved. The intercomparison used data collected at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site and included 18 different algorithms to evaluate their retrieved LWP, optical depth, and effective radii. Surprisingly, evaluation of the simplest case, a single-layer overcast stratocumulus, revealed that huge discrepancies exist among the various techniques, even among different algorithms that are in the same general classification. This suggests that, despite considerable advances that have occurred in the field, much more work must be done, and we discuss potential avenues for future research.) IS - 2 JF - Bulletin of the American Meteorological Society EP - 190 TI - Thin Liquid Water Clouds: Their Importance and Our Challenge VL - 88 SP - 177 KW - boundarylayer KW - clouds KW - clouds-low KW - remotesensing AU - Turner, DD AU - Vogelmann, AM AU - Austin, RT AU - Barnard, JC AU - Cady-Pereira, K AU - Chiu, JC AU - Clough, SA AU - Flynn, C AU - Khaiyer, MM AU - Liljegren, J AU - Johnson, K AU - Lin, B AU - Long, C AU - Marshak, A AU - Matrosov, SY AU - Mcfarlane, SA AU - Miller, M AU - Min, Q AU - Minnis, P AU - O'Hirok, W AU - Wang, Z AU - Wiscombe, W PY - 2007/02// ER -