Role of Convective Entrainment in Spatial Distributions of and Temporal Variations in Precipitation over Tropical Oceans

Abstract The authors demonstrate that an appropriate treatment of convective entrainment is essential for determining spatial distributions of and temporal variations in precipitation. Four numerical experiments are performed using atmospheric models with different entrainment characteristics: a control experiment (Ctl), a no-entrainment experiment (NoEnt), an original Arakawa–Schubert experiment (AS), and an AS experiment with a simple empirical suppression of convection depending on cloud-layer humidity (ASRH). The fractional entrainment rates of AS and ASRH are constant for each cloud type and are very small in the lower troposphere compared with those in the Ctl, in which half of the buoyancy-generated energy is consumed by entrainment. Spatial and temporal variations in the observed precipitation are satisfactorily reproduced in the Ctl, but their amplitudes are underestimated with a so-called double intertropical convergence zone bias in the NoEnt and AS. The spatial variation is larger in the Ctl because convection is more active over humid ascending regions and more suppressed over dry subsidence regions. Feedback processes involving convection, the large-scale circulation, free tropospheric moistening by congestus, and radiation enhance the variations. The temporal evolution of precipitation events is also more realistic in the Ctl, because congestus moistens the midtroposphere, and large precipitation events occur once sufficient moisture is available. The large entrainment in the lower troposphere, increasing free tropospheric moistening by congestus and enhancing the coupling of convection to free tropospheric humidity, is suggested to be important for the realistic spatial and temporal variations.

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Model-Assisted Analysis of Spatial and Temporal Variations in Fruit Temperature and Transpiration Highlighting the Role of Fruit Development

PLoS ONE ◽

10.1371/journal.pone.0092532 ◽

2014 ◽

Vol 9 (3) ◽

pp. e92532 ◽

Cited By ~ 9

Author(s):

Thibault Nordey ◽

Mathieu Léchaudel ◽

Marc Saudreau ◽

Jacques Joas ◽

Michel Génard

Keyword(s):

Fruit Development ◽

Temporal Variations ◽

Spatial And Temporal Variations ◽

Assisted Analysis

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Regional Climatic Features of the Arabian Peninsula

Atmosphere ◽

10.3390/atmos10040220 ◽

2019 ◽

Vol 10 (4) ◽

pp. 220 ◽

Cited By ~ 10

Author(s):

Patlakas ◽

Stathopoulos ◽

Flocas ◽

Kalogeri ◽

Kallos

Keyword(s):

Large Scale ◽

Arabian Peninsula ◽

Regional Climate ◽

Atmospheric Model ◽

Temporal Variations ◽

Spatial And Temporal Variations ◽

Spatial Distance ◽

Temperature Extremes ◽

Mean Temperature ◽

Maximum Temperatures

The climate of the Arabian Peninsula is characterized by significant spatial and temporal variations, due to its complex topography and the large-scale atmospheric circulation. Furthermore, the role of dust in the formation of regional climate is considered to be crucial. In this work, the regional climatology for the Arabian Peninsula has been studied by employing a high resolution state of the art atmospheric model that included sophisticated physical parameterization schemes and online treatment of natural aerosol particles. The simulations covered a 30-year period (1986–2015) with a temporal resolution of 3 h and a spatial distance of 9 km. The main focus was given to the spatial and temporal variations of mean temperature and temperature extremes, wind speed and direction, and relative humidity. The results were evaluated using in situ measurements indicating a good agreement. An examination of possible climatic changes during the present climate was also performed through a comprehensive analysis of the trends of mean temperature and temperature extremes. The statistical significant trend values were overall positive and increased over the northwestern parts of the examined area. Similar spatial distributions were found for the daily minimum and maximum temperatures. Higher positive values emerged for the daily maxima.

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Spatial and temporal variations of precipitation concentration and their relationships with large-scale atmospheric circulations across Northeast China

Atmospheric Research ◽

10.1016/j.atmosres.2019.02.008 ◽

2019 ◽

Vol 222 ◽

pp. 62-73 ◽

Cited By ~ 15

Author(s):

Rui Wang ◽

Jiquan Zhang ◽

Enliang Guo ◽

Chunli Zhao ◽

Tiehua Cao

Keyword(s):

Northeast China ◽

Large Scale ◽

Temporal Variations ◽

Spatial And Temporal Variations ◽

Atmospheric Circulations ◽

Precipitation Concentration

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Role of spatial and temporal variations in the computation of radiative forcing due to sulphate aerosols: A regional study

CrossRef Listing of Deleted DOIs ◽

10.1256/0035900021643610 ◽

2002 ◽

Vol 128 (581) ◽

pp. 973-989 ◽

Cited By ~ 24

Author(s):

Gunnar Myhre ◽

Jan E. Jonson ◽

Jerzy Bartnicki ◽

Frode Stordal ◽

Keith P. Shine

Keyword(s):

Radiative Forcing ◽

Temporal Variations ◽

Spatial And Temporal Variations ◽

Regional Study ◽

Sulphate Aerosols

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ROLE OF THE COLORED NOISE IN SPATIO-TEMPORAL BEHAVIOR OF TWO COMPETING SPECIES

Fluctuation and Noise Letters ◽

10.1142/s0219477505002744 ◽

2005 ◽

Vol 05 (02) ◽

pp. L337-L342 ◽

Cited By ~ 6

Author(s):

D. VALENTI ◽

A. FIASCONARO ◽

B. SPAGNOLO

Keyword(s):

Noise Intensity ◽

Large Scale ◽

Colored Noise ◽

Spatial Distributions ◽

Temporal Behavior ◽

Spatial Correlations ◽

Interacting Species ◽

Spatio Temporal ◽

Nonmonotonic Behavior

We study the spatial distributions of two randomly interacting species, in the presence of an external multiplicative colored noise. The dynamics of the ecosystem is described by a coupled map lattice model. We find a nonmonotonic behavior in the formation of large scale spatial correlations as a function of the multiplicative colored noise intensity. This behavior is shifted towards higher values of the noise intensity for increasing correlation time of the noise.

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On the imprint of the mesoscale organization of tradewind clouds at cloud base and below

10.5194/egusphere-egu21-14901 ◽

2021 ◽

Author(s):

Sandrine Bony ◽

Pierre-Etienne Brilouet ◽

Patrick Chazette ◽

Pierre Coutris ◽

Julien Delanoë ◽

...

Keyword(s):

Large Scale ◽

Lower Troposphere ◽

Cloud Base ◽

Trade Wind ◽

Tropical Atlantic ◽

Lidar Measurements ◽

Research Aircraft ◽

Cloud Patterns

Trade-wind clouds can exhibit different patterns of mesoscale organization. These patterns were observed during the EUREC4A (Elucidating the role of cloud-circulation coupling in climate) field campaign that took place in Jan-Feb 2020 over the western tropical Atlantic near Barbados: while the HALO aircraft was observing clouds from above and was characterizing the large-scale environment with dropsondes, the ATR-42 research aircraft was flying in the lower troposphere, characterizing clouds and turbulence with horizontal radar-lidar measurements and in-situ probes and sensors. By analyzing these data for different cloud patterns, we investigate the extent to which the cloud organization is imprinted in cloud-base properties and subcloud-layer heterogeneities. The implications of our findings for understanding the roots of the mesoscale organization of tradewind clouds will be discussed.

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Response of Humidity and Clouds to Tropical Deep Convection

Journal of Climate ◽

10.1175/2008jcli2452.1 ◽

2009 ◽

Vol 22 (9) ◽

pp. 2389-2404 ◽

Cited By ~ 38

Author(s):

Mark D. Zelinka ◽

Dennis L. Hartmann

Keyword(s):

Large Scale ◽

Deep Convection ◽

Lower Troposphere ◽

Upward Motion ◽

Temporal Separation ◽

Convective Event ◽

Clear Sky ◽

Intense Precipitation ◽

Upper Level ◽

Precipitation Events

Abstract Currently available satellite data can be used to track the response of clouds and humidity to intense precipitation events. A compositing technique centered in space and time on locations experiencing high rain rates is used to detail the characteristic evolution of several quantities measured from a suite of satellite instruments. Intense precipitation events in the convective tropics are preceded by an increase in low-level humidity. Optically thick cold clouds accompany the precipitation burst, which is followed by the development of spreading upper-level anvil clouds and an increase in upper-tropospheric humidity over a broader region than that occupied by the precipitation anomalies. The temporal separation between the convective event and the development of anvil clouds is about 3 h. The humidity increase at upper levels and the associated decrease in clear-sky longwave emission persist for many hours after the convective event. Large-scale vertical motions from reanalysis show a coherent evolution associated with precipitation events identified in an independent dataset: precipitation events begin with stronger upward motion anomalies in the lower troposphere, which then evolve toward stronger upward motion anomalies in the upper troposphere, in conjunction with the development of anvil clouds. Greater upper-tropospheric moistening and cloudiness are associated with larger-scale and better-organized convective systems, but even weaker, more isolated systems produce sustained upper-level humidity and clear-sky outgoing longwave radiation anomalies.

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Precipitation scaling in the tropics with a convection-permitting model

10.5194/egusphere-egu2020-6890 ◽

2020 ◽

Author(s):

Daniel Argüeso ◽

Alejandro Di Luca ◽

Nicolas Jourdain ◽

Romualdo Romero ◽

Victor Homar

Keyword(s):

Water Vapor ◽

Large Scale ◽

Potential Temperature ◽

Lower Troposphere ◽

Dew Point ◽

Precipitation Extremes ◽

Maritime Continent ◽

Near Surface ◽

Intense Precipitation ◽

Precipitation Events

The Maritime Continent is a major convective area and precipitation processes in the region pose great challenges to atmospheric models. A combination of large-scale drivers, such as the Madden-Julian Oscillation and ENSO, and fine-scale processes, such as orographically-forced precipitation, land-sea circulations and tropical convection, governs rainfall in the Maritime Continent. The use of convection-permitting models in the region has shown improved performance in the simulation of precipitation characteristics that are key for the region (i.e. diurnal cycle).Most of the rainfall occurring over land is concentrated in the late afternoon and precipitation extremes often occur over short periods of time. The availability of water vapor in the lower troposphere and the high water-holding capacity of a warm atmosphere favors very intense precipitation events, according to the Clausius-Clapeyron relationship. In a warming climate, a full understanding of the so-called precipitation scaling with temperature is thus crucial. However, this potential generally requires the atmosphere be saturated and convection be initiated to become effective. Using a regional climate model operating at convection-permitting scales over 3 consecutive wet seasons, we investigate the response of intense precipitation to temperature.In this presentation, we examine different approaches to relate precipitation extremes to near-surface temperature and dew-point temperature. We show that the relationship breaks at certain thresholds that are relatively uniform across islands. The region is well supplied with water vapor and the break is not explained by a deficit in water vapor, unlike previously proposed for other water-limited regions. We identify possible reasons for this behavior, such as the lack of environmental conditions that trigger convection. In this context, we explore the sensitivity of the modelling system to the convection representation (explicit vs. parameterized) and discuss the implications for future changes in intense precipitation events. Finally, we put forward the use of specific variables, such as temperature and equivalent potential temperature integrated in the vertical. These variables not only are coherent with the CC equation but also acknowledge the different warming rates near the surface and at higher tropospheric levels, where precipitating processes actually occur.

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