scholarly journals Role of atmospheric aerosol concentration on deep convective precipitation: Cloud-resolving model simulations

2007 ◽  
Vol 112 (D24) ◽  
Author(s):  
Wei-Kuo Tao ◽  
Xiaowen Li ◽  
Alexander Khain ◽  
Toshihisa Matsui ◽  
Stephen Lang ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Aerosol Concentration ◽  
Convective Precipitation ◽  
Model Simulations ◽  
Cloud Resolving Model

scholarly journals The Role of Aerosols in Convective Processes during the Midsummer Drought in the Caribbean

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Nathan Hosannah ◽  
Hamed Parsiani ◽  
Jorge E. González
Keyword(s):  
Heavy Precipitation ◽  
Atmospheric Modeling ◽  
Dew Point ◽  
Saharan Dust ◽  
Convective Precipitation ◽  
Precipitation Event ◽  
Atmospheric Conditions ◽  
Cloud Resolving Model ◽  
The Caribbean

Saharan dust (SD) heavily impacts convective precipitation in the Caribbean. To better understand the role of SD in precipitation development during the midsummer drought (MSD), an observational campaign, centered at the city of Mayagüez, Puerto Rico (18.21 N, 67.13 W), between 3 June and 15 July 2014, was conducted in order to select a range of atmospheric conditions to be simulated using the Regional Atmospheric Modeling System (RAMS) cloud resolving model under “no SD” and “SD” conditions. The events included one dry day with moderate-heavy SD, one localized moderate rainfall event with moderate SD, one island-wide light precipitation event with heavy SD, and one island-wide heavy precipitation event with light-moderate SD. Model results show that (1) precipitation results are improved when compared with observation with the presence of SD, (2) precipitation, cloud fraction, dew point temperatures, and humidity are significantly reduced under SD conditions, (3) precipitation can occur when SD is removed for a dry day, (4) there is evidence of rain being delayed due to the presence of SD without rainfall intensity or accumulation increases, (5) liquid mixing ratio increases of up to 1.4 g kg−1occur in the absence of SD, and (6) vertical wind increases of up to 0.8 m s−1occur in the absence of SD.

Past climate and the role of ocean heat transport: Model simulations for the Cretaceous

1993 ◽  
Vol 8 (6) ◽  
pp. 785-798 ◽  
Author(s):  
Eric J. Barron ◽  
William H. Peterson ◽  
David Pollard ◽  
Starley Thompson
Keyword(s):  
Heat Transport ◽  
Transport Model ◽  
Ocean Heat Transport ◽  
Past Climate ◽  
Model Simulations

scholarly journals A numerical study of the windstorm Klaus: sensitivity to sea surface temperature

2014 ◽  
Vol 57 (5) ◽  
Author(s):  
Nazario Tartaglione ◽  
Rodrigo Caballero
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Numerical Study ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Moisture Convergence ◽  
Convective Precipitation ◽  
Limited Area ◽  
Weather Forecasts

<p>This article investigates the role of sea surface temperature (SST) as well as the effects of evaporation and moisture convergence on the evolution of cyclone Klaus, which occurred on January 23 and 24, 2009. To elucidate the role of sea surface temperature (SST) and air–sea fluxes in the dynamics of the cyclone, ten hydrostatic mesoscale simulations were performed by Bologna Limited Area Model (BOLAM). The first one was a control experiment with European Centre for Medium-Range Weather Forecasts (ECMWF) SST analysis. The nine following simulations are sensitivity experiments where the SST are obtained by adding a constant value by 1 to 9 K to the ECMWF field. Results show that a warmer sea increases the surface latent heat fluxes and the moisture convergence, favoring the development of convection in the storm. Convection is affected immediately by the increased SST. Later on, drop of mean sea level pressure (MSLP) occurs together with increasing of surface winds. The cyclone trajectory is not sensitive to change in SST differently from MSLP and convective precipitation.</p>

scholarly journals tobac 1.2: towards a flexible framework for tracking and analysis of clouds in diverse datasets

2019 ◽  
Vol 12 (11) ◽  
pp. 4551-4570 ◽  
Author(s):  
Max Heikenfeld ◽  
Peter J. Marinescu ◽  
Matthew Christensen ◽  
Duncan Watson-Parris ◽  
Fabian Senf ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Longwave Radiation ◽  
Geostationary Satellite ◽  
Model Assessment ◽  
Model Simulations ◽  
Cloud Properties ◽  
Level Data ◽  
Different Types ◽  
Cloud Resolving Model ◽  
High Level

Abstract. We introduce tobac (Tracking and Object-Based Analysis of Clouds), a newly developed framework for tracking and analysing individual clouds in different types of datasets, such as cloud-resolving model simulations and geostationary satellite retrievals. The software has been designed to be used flexibly with any two- or three-dimensional time-varying input. The application of high-level data formats, such as Iris cubes or xarray arrays, for input and output allows for convenient use of metadata in the tracking analysis and visualisation. Comprehensive analysis routines are provided to derive properties like cloud lifetimes or statistics of cloud properties along with tools to visualise the results in a convenient way. The application of tobac is presented in two examples. We first track and analyse scattered deep convective cells based on maximum vertical velocity and the three-dimensional condensate mixing ratio field in cloud-resolving model simulations. We also investigate the performance of the tracking algorithm for different choices of time resolution of the model output. In the second application, we show how the framework can be used to effectively combine information from two different types of datasets by simultaneously tracking convective clouds in model simulations and in geostationary satellite images based on outgoing longwave radiation. The tobac framework provides a flexible new way to include the evolution of the characteristics of individual clouds in a range of important analyses like model intercomparison studies or model assessment based on observational data.

Vertical distribution of atmospheric aerosol concentration at xianghe

2004 ◽  
Vol 2 (6) ◽  
pp. 256-260
Author(s):  
Li Xu ◽  
Guangyu Shi ◽  
Jun Zhou ◽  
Yasunobu Iwasaka
Keyword(s):  
Vertical Distribution ◽  
Atmospheric Aerosol ◽  
Aerosol Concentration

Elevation-Dependent Climate Change in the European Alps

2020 ◽  
Author(s):  
Michael Kuhn ◽  
Marc Olefs
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Global Warming ◽  
Atmospheric Pressure ◽  
Atmospheric Aerosol ◽  
European Alps ◽  
Model Simulations ◽  
Vapor Cloud ◽  
Pressure Water ◽  
Time Changes

Elevation-dependent climate change has been observed in the European Alps in the context of global warming and as a consequence of Alpine orography. It is most obvious in elevation-dependent warming, conveniently defined as the linear regression of the time series of temperatures against elevation, and it reaches values of several tenths of a degree per 1,000 m elevation per decade. Observed changes in temperature have forced changes in atmospheric pressure, water vapor, cloud condensation, fluxes of infrared and solar radiation, snow cover, and evaporation, which have affected the Alpine surface energy and water balance in different ways at different elevations. At the same time, changes in atmospheric aerosol optical depth, in atmospheric circulation, and in the frequency of weather types have contributed to the observed elevation-dependent climate change in the European Alps. To a large extent, these observations have been reproduced by model simulations.

scholarly journals Parameter Modulation of Madden-Julian Oscillation Behaviors in BCC_CSM1.2: The Key Role of Moisture-Shallow Convection Feedback

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 241 ◽  
Author(s):  
Kai Huang ◽  
Hong-Li Ren ◽  
Xiangwen Liu ◽  
Pengfei Ren ◽  
Yuntao Wei ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Latin Hypercube Sampling ◽  
Heavy Precipitation ◽  
Convective Precipitation ◽  
Physical Parameters ◽  
Madden Julian Oscillation ◽  
Shallow Convection ◽  
Climate System Model ◽  
New Strategy

To reveal key parameter-related physical mechanisms in simulating Madden-Julian Oscillation (MJO), seven physical parameters in the convection and cloud parameterization schemes of Beijing Climate Center Climate System Model (BCC_CSM1.2) are perturbed with Latin hypercube sampling method. A new strategy is proposed to select runs with good and poor MJO simulations among 85 generated ones. Outputs and parameter values from good and poor simulations are composited separately for comparison. Among the seven chosen parameters, a decreased value of precipitation efficiency for shallow convection, higher values of relative humidity threshold for low stable clouds and evaporation efficiency for deep convective precipitation are crucial to simulate a better MJO. Changes of the three parameters act together to suppress heavy precipitation and increase the frequency of light rainfall over the Indo-Pacific region, supplying more moisture in low and middle troposphere. As a result of a wetter lower troposphere ahead of the MJO main convection, the low-level moisture preconditioning along with the leading shallow convection tends to be enhanced, favorable for MJO’s further development and eastward propagation. The MJO’s further propagation across the Maritime Continent (MC) in good simulations is accompanied with more land precipitation dominated by shallow convection. Therefore, the above-mentioned three parameters are found to be crucial parameters out of the seven ones for MJO simulation, providing an inspiration for better MJO simulation and prediction with this model. This work is valuable as it highlights the key role of moisture-shallow convection feedback in the MJO dynamics.

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