caa a22 4500 475777581 CHVBK 20180406123635.0 cr unu---uuuuu 170329e20000401xx s 000 0 eng 10.1023/A:1002434314651 doi (NATIONALLICENCE)springer-10.1023/A:1002434314651 The Sensitivity Of A Stratocumulus Transition: Model Simulations Of The Astex First Lagrangian [Elektronische Daten] [Gunilla Svensson, Michael Tjernström, Darko Koračin] In this study, a one-dimensional ensemble-average model is used to simulatethe Atlantic Stratocumulus Transition Experiment firstLagrangian, where the same airmass was followed from the subtropical high pressure region en route towards the trade wind region. The airmass experiences increasing sea-surface temperature and achange from subsidence to weak ascent on its way south. Thiscauses the marine boundary layer (MBL)to grow and the cloud deck to change from a solid stratocumulus deck tomore broken stratocumulus clouds with cumulus cloudsdeveloping beneath, and reaching up into the stratocumulus clouds. A control run is analyzed and compared in detail with theobservations. Both a statistical evaluation and a more subjective evaluation are performed, where both establish confidencein the model performance. The model captures the MBL growth and the cloudliquid water, as well as the drizzle flux, is well predicted by the model.A sensitivity study was performed with the objective of examining theMBL and the cloud response to external and internal 'forces'.The results show that, if drizzle formation is not allowed,unrealistically high cloud liquid water mixing ratios are predicted. Even though the drizzle flux is very small, it is still important for the water budget of the MBL and for the boundary-layer dynamics.We also found that the sea-surface temperature increase is more important for the increasing cloud top height than the synoptic-scale divergence fields. However, the synoptic-scale subsidence is crucial during the first day, when the sea-surface temperature was constant, in keepingthe cloud top at a constant height. Drizzle evaporation below the cloud base seems to be important for below-cloud condensation. The drizzle predictions are significantly altered when the prescribed cloud droplet and/or drizzle drop numbers are altered. Kluwer Academic Publishers, 2000 Marine stratocumulus nationallicence Cloud-topped boundary layer nationallicence Drizzle nationallicence Numerical modelling nationallicence ASTEX nationallicence Svensson Gunilla Department of Meteorology, Stockholm University, Stockholm, Sweden aut Tjernström Michael Department of Meteorology, Stockholm University, Stockholm, Sweden aut Koračin Darko Desert Research Institute, Reno, Nevada, U.S.A. aut Boundary-Layer Meteorology Kluwer Academic Publishers 95/1(2000-04-01), 57-90 0006-8314 95:1<57 2000 95 10546 https://doi.org/10.1023/A:1002434314651 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1002434314651 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Svensson Gunilla Department of Meteorology, Stockholm University, Stockholm, Sweden aut NATIONALLICENCE 700 1- Tjernström Michael Department of Meteorology, Stockholm University, Stockholm, Sweden aut NATIONALLICENCE 700 1- Koračin Darko Desert Research Institute, Reno, Nevada, U.S.A aut NATIONALLICENCE 773 0- Boundary-Layer Meteorology Kluwer Academic Publishers 95/1(2000-04-01), 57-90 0006-8314 95:1<57 2000 95 10546 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer