Interaction of Sea Breeze and Deep Convection over the Northeastern Adriatic Coast: An Analysis of Sensitivity Experiments Using a High-Resolution Mesoscale Model

2017 ◽  
Vol 174 (11) ◽  
pp. 4197-4224 ◽  
Author(s):  
Gabrijela Kehler-Poljak ◽  
Maja Telišman Prtenjak ◽  
Marko Kvakić ◽  
Kristina Šariri ◽  
Željko Večenaj
Keyword(s):  
High Resolution ◽  
Mesoscale Model ◽  
Deep Convection ◽  
Sea Breeze ◽  
Sensitivity Experiments ◽  
Adriatic Coast

scholarly journals Investigating Hector Convective Development and Microphysical Structure Using High-Resolution Model Simulations, Ground-Based Radar Data, and TRMM Satellite Data

2014 ◽  
Vol 71 (4) ◽  
pp. 1353-1370 ◽  
Author(s):  
Sabrina Gentile ◽  
Rossella Ferretti ◽  
Frank Silvio Marzano
Keyword(s):  
High Resolution ◽  
Conceptual Model ◽  
Vertical Structure ◽  
Mesoscale Model ◽  
Tropical Rainfall Measuring Mission ◽  
Sea Breeze ◽  
Radar Data ◽  
Full Life Cycle ◽  
Resolution Model ◽  
High Resolution Model

Abstract One event of a tropical thunderstorm typically observed in northern Australia, known as Hector, is investigated using high-resolution model output from the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) observations from a ground-based weather radar located in Berrimah (Australia) and data from the Tropical Rainfall Measuring Mission (TRMM) satellite. The analysis is carried out by tracking the full life cycle of Hector from prestorm stage to the decaying stage. In both the prestorm stage, characterized by nonprecipitating cells, and the triggering stage, when the Hector storm is effectively initiated, an analysis is performed with the aid of high-spatial-and-temporal-resolution MM5 output and the Berrimah ground-based radar imagery. During the mature (“old”) stage of Hector, considering the conceptual model for tropical convection suggested by R. Houze, TRMM Microwave Imager satellite-based data were added to ground-based radar data to analyze the storm vertical structure (dynamics, thermodynamics, and hydrometeor contents). Model evaluation with respect to observations (radar reflectivity and TRMM data) suggests that MM5 performed fairly well in reproducing the dynamics of Hector, providing support to the assertion that the strength of convection, in terms of vertical velocity, largely contributes to the vertical distribution of hydrometeors. Moreover, the stages of the storm and its vertical structure display good agreement with Houze’s aforementioned conceptual model. Finally, it was found that the most important triggering mechanisms for this Hector event are topography, the sea breeze, and a gust front produced by previous convection.

scholarly journals Eastward-Propagating Undular Bores over Cape York Peninsula

2009 ◽  
Vol 137 (8) ◽  
pp. 2632-2645 ◽  
Author(s):  
Robert A. Goler
Keyword(s):  
West Coast ◽  
East Coast ◽  
Mesoscale Model ◽  
Deep Convection ◽  
Sea Breeze ◽  
Morning Glory ◽  
Sudden Increase ◽  
Stable Layer ◽  
The West ◽  
Cape York

Abstract The existence of eastward-propagating bores over Cape York Peninsula is shown from data obtained during the Gulf Lines Experiment (GLEX) conducted during September and October 2002 and from numerical modeling experiments. The disturbances were detected regularly at two stations, observable on 24 days during the 40-day experiment. The passage of a typical disturbance exhibits a sudden increase in pressure of around 1 hPa, often accompanied by undulations, and a change in the wind speed and direction from an easterly to a westerly flow. Disturbances were not observed during days of strong easterly flow. A two-dimensional nonhydrostatic mesoscale model is used to examine the formation of these disturbances. It is shown that the west coast sea breeze is shallow and does not penetrate far inland because of the opposing low-level easterly flow. In contrast, the east coast sea breeze is deeper and is less stable because it is modified by daytime convective mixing as it crosses the peninsula. As the east coast sea breeze overrides the west coast sea breeze, the west coast sea breeze produces an eastward-propagating bore on the stable layer laid down by the east coast sea breeze. About 2 h after generation, the bore becomes undular. These eastward-propagating disturbances are shown to be associated with the westward-propagating north Australian cloud line and the northeasterly morning glory. In addition, it is shown here that an undular bore can be formed when cold-air downdrafts from afternoon deep convection enter the stable layer created by the east coast sea breeze. Four events from GLEX are believed to have been formed in this way. The eastward-propagating disturbances produced in this way are accompanied neither by the north Australian cloud line nor by the northeasterly morning glory.

scholarly journals Influences of the Monsoon Trough and Arabian Heat Low on Summer Rainfall over the United Arab Emirates

2018 ◽  
Vol 146 (5) ◽  
pp. 1383-1403 ◽  
Author(s):  
Daniel F. Steinhoff ◽  
Roelof Bruintjes ◽  
Joshua Hacker ◽  
Teddie Keller ◽  
Christopher Williams ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Mesoscale Model ◽  
Deep Convection ◽  
Arabian Gulf ◽  
Summer Rainfall ◽  
Sea Breeze ◽  
Cyclonic Circulation ◽  
Moist Air ◽  
Sea Level Pressure ◽  
Heat Low

Abstract The factors responsible for rare summertime rainfall over portions of the United Arab Emirates (UAE), which have not been previously explored in detail, are elucidated with the Climate Forecast System Reanalysis and WRF mesoscale model simulations. The simulations show associations between active phases of the southwest Asian monsoon and intensification of the Arabian heat low, leading up to UAE rainfall events. Variability in the location and strength of the Arabian heat low circulation, which differs from the static portrayal in climatological minimum sea level pressure (MSLP), can affect the development of deep convection over the UAE. Analysis of the vorticity equation for a two-day case study period confirms that convergence is solely responsible for the spinup and maintenance of the primary heat low circulation. Convergence is also responsible for the spinup of a separate cyclonic circulation over the eastern UAE, which propagates offshore to the Arabian Gulf during morning hours. This cyclonic circulation advects moist air onshore over the western UAE, and deep convection follows from inland horizontal convective rolls and interaction with the approaching sea-breeze front. The development of widespread deep convection is shown to be most favorable during the decay phase of the Arabian heat low, when the preconditioned moist air is not replaced by drier continental flow, and the vertical profiles of temperature and moisture are also more favorable. Three other rainfall cases are briefly discussed to illustrate how the strength and geographic position of the Arabian heat low can affect rainfall characteristics over the UAE.

High-Resolution Climate Change Impact Analysis on Expected Future Water Availability in the Upper Jordan Catchment and the Middle East

2014 ◽  
Vol 15 (4) ◽  
pp. 1517-1531 ◽  
Author(s):  
Gerhard Smiatek ◽  
Harald Kunstmann ◽  
Andreas Heckl
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Water Availability ◽  
Impact Analysis ◽  
River Flow ◽  
Climate Model ◽  
Mesoscale Model ◽  
Global Climate Model ◽  
Full Range ◽  
The Impact

Abstract The impact of climate change on the future water availability of the upper Jordan River (UJR) and its tributaries Dan, Snir, and Hermon located in the eastern Mediterranean is evaluated by a highly resolved distributed approach with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) run at 18.6- and 6.2-km resolution offline coupled with the Water Flow and Balance Simulation Model (WaSiM). The MM5 was driven with NCEP reanalysis for 1971–2000 and with Hadley Centre Coupled Model, version 3 (HadCM3), GCM forcings for 1971–2099. Because only one regional–global climate model combination was applied, the results may not give the full range of possible future projections. To describe the Dan spring behavior, the hydrological model was extended by a bypass approach to allow the fast discharge components of the Snir to enter the Dan catchment. Simulation results for the period 1976–2000 reveal that the coupled system was able to reproduce the observed discharge rates in the partially karstic complex terrain to a reasonable extent with the high-resolution 6.2-km meteorological input only. The performed future climate simulations show steadily rising temperatures with 2.2 K above the 1976–2000 mean for the period 2031–60 and 3.5 K for the period 2070–99. Precipitation trends are insignificant until the middle of the century, although a decrease of approximately 12% is simulated. For the end of the century, a reduction in rainfall ranging between 10% and 35% can be expected. Discharge in the UJR is simulated to decrease by 12% until 2060 and by 26% until 2099, both related to the 1976–2000 mean. The discharge decrease is associated with a lower number of high river flow years.

scholarly journals A Comparative Evaluation of a Mesoscale Model and Atmospheric Global Circulation Model for Air Quality Simulation: A Multiscale, Multisite Evaluation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
P. Goswami ◽  
J. Baruah
Keyword(s):  
High Resolution ◽  
Mesoscale Model ◽  
Large City ◽  
Circulation Model ◽  
Urban Pollution ◽  
Atmospheric Pollutants ◽  
Scale Model ◽  
Global Circulation Model ◽  
Global Circulation ◽  
Meso Scale

Concentrations of atmospheric pollutants are strongly influenced by meteorological parameters like rainfall, relative humidity and wind advection. Thus accurate specifications of the meteorological fields, and their effects on pollutants, are critical requirements for successful modelling of air pollution. In terms of their applications, pollutant concentration models can be used in different ways; in one, short term high resolution forecasts are generated to predict and manage urban pollution. Another application of dynamical pollution models is to generate outlook for a given airbasin, such as over a large city. An important question is application-specific model configuration for the meteorological simulations. While a meso-scale model provides a high-resolution configuration, a global model allows better simulation of large-sale fields through its global environment. Our objective is to comparatively evaluate a meso-scale atmospheric model (MM5) and atmospheric global circulation model (AGCM) in simulating different species of pollutants over different airbasins. In this study we consider four locations: ITO (Central Delhi), Sirifort (South Delhi), Bandra (Mumbai) and Karve Road (Pune). The results show that both the model configurations provide comparable skills in simulation of monthly and annual loads, although the skill of the meso-scale model is somewhat higher, especially at shorter time scales.

scholarly journals Comparison of high-resolution wind fields extracted from TerraSAR-X SAR imagery with predictions from the WRF mesoscale model

2012 ◽  
Vol 117 (C2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Donald R. Thompson ◽  
Jochen Horstmann ◽  
Alexis Mouche ◽  
Nathaniel S. Winstead ◽  
Raymond Sterner ◽  
...  
Keyword(s):  
High Resolution ◽  
Mesoscale Model ◽  
Wind Fields ◽  
Sar Imagery

Thermally Driven Diurnally Periodic Wind Signals off the East Coast of China

2015 ◽  
Vol 72 (7) ◽  
pp. 2806-2821 ◽  
Author(s):  
Yu Du ◽  
Richard Rotunno
Keyword(s):  
Linear Theory ◽  
East Coast ◽  
Mesoscale Model ◽  
Maximum Amplitude ◽  
Sea Breeze ◽  
Model Data ◽  
Absolute Time ◽  
Thermally Driven ◽  
Diurnal Wind ◽  
Northeast Coast

The characteristics of thermally driven diurnally periodic wind signals off the east coast of China are studied using hourly model data for the period June 2006–11 simulated with a mesoscale model. Analysis of these model data indicates low-level diurnally periodic wind signals propagate eastward off the southeast coast, whereas diurnal wind variations off the northeast coast are nearly in phase. It is found that a simple 2D linear land–sea-breeze model with friction can capture this main difference in propagation character with respect to latitude. Idealized simulations using a simplified version of the mesoscale model that includes surface heating and terrain are found to explain certain features not captured by the present linear theory such as the absolute time phase and cross-coast location of the maximum amplitude of the diurnally periodic winds.

scholarly journals Role of land state in a high resolution mesoscale model for simulating the Uttarakhand heavy rainfall event over India

2016 ◽  
Vol 125 (3) ◽  
pp. 475-498 ◽  
Author(s):  
P V Rajesh ◽  
S Pattnaik ◽  
D Rai ◽  
K K Osuri ◽  
U C Mohanty ◽  
...  
Keyword(s):  
High Resolution ◽  
Heavy Rainfall ◽  
Mesoscale Model ◽  
Rainfall Event ◽  
Heavy Rainfall Event

scholarly journals Ensemble forecasting with a stochastic convective parametrization based on equilibrium statistics

2011 ◽  
Vol 11 (11) ◽  
pp. 30457-30485 ◽  
Author(s):  
P. Groenemeijer ◽  
G. C. Craig
Keyword(s):  
Large Scale ◽  
Mesoscale Model ◽  
Initial Conditions ◽  
Deep Convection ◽  
Horizontal Resolution ◽  
Ensemble Forecasting ◽  
Total Variance ◽  
Ensemble Prediction ◽  
Ensemble Prediction System ◽  
The Impact

Abstract. The stochastic Plant-Craig scheme for deep convection was implemented in the COSMO mesoscale model and used for ensemble forecasting. Ensembles consisting of 100 48 h forecasts at 7 km horizontal resolution were generated for a 2000 × 2000 km domain covering central Europe. Forecasts were made for seven case studies and characterized by different large-scale meteorological environments. Each 100 member ensemble consisted of 10 groups of 10 members, with each group driven by boundary and initial conditions from a selected member from the global ECMWF Ensemble Prediction System. The precipitation variability within and among these groups of members was computed, and it was found that the relative contribution to the ensemble variance introduced by the stochastic convection scheme was substantial, amounting to as much as 76% of the total variance in the ensemble in one of the studied cases. The impact of the scheme was not confined to the grid scale, and typically contributed 25–50% of the total variance even after the precipitation fields had been smoothed to a resolution of 35 km. The variability of precipitation introduced by the scheme was approximately proportional to the total amount of convection that occurred, while the variability due to large-scale conditions changed from case to case, being highest in cases exhibiting strong mid-tropospheric flow and pronounced meso- to synoptic scale vorticity extrema. The stochastic scheme was thus found to be an important source of variability in precipitation cases of weak large-scale flow lacking strong vorticity extrema, but high convective activity.

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