著者

STEVENS Bjorn ACQUISTAPACE Claudia HANSEN Akio HEINZE Rieke KLINGER Carolin KLOCKE Daniel RYBKA Harald SCHUBOTZ Wiebke WINDMILLER Julia ADAMIDIS Panagiotis ARKA Ioanna BARLAKAS Vasileios BIERCAMP Joachim BRUECK Matthias BRUNE Sebastian BUEHLER Stefan A. BURKHARDT Ulrike CIONI Guido COSTA-SURÓS Montserrat CREWELL Susanne CRÜGER Traute DENEKE Hartwig FRIEDERICHS Petra HENKEN Cintia Carbajal HOHENEGGER Cathy JACOB Marek JAKUB Fabian KALTHOFF Norbert KÖHLER Martin LAAR Thirza W. van LI Puxi LÖHNERT Ulrich MACKE Andreas MADENACH Nils MAYER Bernhard NAM Christine NAUMANN Ann Kristin PETERS Karsten POLL Stefan QUAAS Johannes RÖBER Niklas ROCHETIN Nicolas SCHECK Leonhard SCHEMANN Vera SCHNITT Sabrina SEIFERT Axel SENF Fabian SHAPKALIJEVSKI Metodija SIMMER Clemens SINGH Shweta SOURDEVAL Odran SPICKERMANN Dela STRANDGREN Johan TESSIOT Octave VERCAUTEREN Nikki VIAL Jessica VOIGT Aiko ZÄNGL Günter

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-021, (Released:2020-01-28)

被引用文献数

85

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More than one hundred days were simulated over very large domains with fine (0.156 km to 2.5 km) grid spacing for realistic conditions to test the hypothesis that storm (kilometer) and large-eddy (hectometer) resolving simulations would provide an improved representation of clouds and precipitation in atmospheric simulations. At scales that resolve convective storms (storm-resolving for short) scales, the vertical velocity variance becomes resolved and a better physical basis is achieved for representing clouds and precipitation. Similar to past studies we find an improved representation of precipitation at kilometer scales, as compared to models with parameterised convection. The main precipitation features (location, diurnal cycle and spatial propagation) are well captured already at kilometer scales, and refining resolution to hectometer scales does not substantially change the simulations in these respects. It does, however, lead to a reduction in the precipitation on the time-scales considered – most notably over the Tropical ocean. Changes in the distribution of precipitation, with less frequent extremes are also found in simulations incorporating hecto-meter scales. Hectometer scales appear more important for the representation of clouds, and make it possible to capture many important aspects of the cloud field, from the vertical distribution of cloud cover, to the distribution of cloud sizes, to the diel (daily) cycle. Qualitative improvements, particularly in the ability to differentiate cumulus from stratiform clouds, are seen when reducing the grid spacing from kilometer to hectometer scales. At the hectometer scale new challenges arise, but the similarity of observed and simulated scales, and the more direct connection between the circulation and the unconstrained degrees of freedom make these challenges less daunting. This quality, combined with an already improved simulation as compared to more parameterised models, underpins our conviction that the use and further development of storm-resolving models offers exciting opportunities for advancing understanding of climate and climate change.

著者

MA Libin PETERS Karsten WANG Bin LI Juan

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2019-053, (Released:2019-06-28)

被引用文献数

11

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Based on the preceding work, the influence of the Stochastic Multicloud Model (SMCM) on the Madden-Julian Oscillation (MJO) in the state-of-the-art ECHAM6.3 at-mosphere general circulation model (AGCM) is further evaluated. The evaluation present-ed here is based on six recently proposed dynamics-oriented diagnostic metrics. Lag-longitude correlation maps of surface precipitation in the East Indian and West Pacific Oceans confirm the previously found improved representation of the MJO in the modi-fied ECHAM6.3 model compared to the standard configuration. In fact, the modified ECHAM6.3 outperforms the default ECHAM6.3 in five of the six MJO-related diagnos-tics evaluated here. In detail, the modified ECHAM6.3 (1) successfully models the east-ward propagation of boundary layer moisture convergence (BLMC); (2) captures the rearward tilted structure of equivalent potential temperature (EPT) in the lower tropo-sphere and forward tilted structure of EPT in the upper troposphere; (3) exhibits the rear-ward tilted structure of equatorial diabatic heating in the lower troposphere; (4) adequate-ly simulates the MJO-related horizontal circulation at 850 and 200 hPa as well as the 300 hPa diabatic heating structure. These evaluations confirm the crucial role of convective-parameterization formulation on GCM-simulated MJO dynamics and support the further application and exploration of the SMCM-concept in full-complexity GCMs.