scholarly journals The Tokar Gap Jet: Regional Circulation, Diurnal Variability, and Moisture Transport Based on Numerical Simulations

2015 ◽  
Vol 28 (15) ◽  
pp. 5885-5907 ◽  
Author(s):  
Shannon R. Davis ◽  
Lawrence J. Pratt ◽  
Houshuo Jiang
Keyword(s):  
Red Sea ◽  
Moisture Transport ◽  
Arabian Peninsula ◽  
Wrf Model ◽  
Sea Breeze ◽  
Lagrangian Model ◽  
East African ◽  
Diurnal Variability ◽  
Mesoscale Convective ◽  
Wind Regimes

Abstract The structure, variability, and regional connectivity of the Tokar Gap jet (TGJ) are described using WRF Model analyses and supporting atmospheric datasets from the East African–Red Sea–Arabian Peninsula (EARSAP) region during summer 2008. Sources of the TGJ’s unique quasi-diurnal nature and association with atypically high atmospheric moisture transport are traced back to larger-scale atmospheric dynamics influencing its forcing. These include seasonal shifts in the intertropical convergence zone (ITCZ), variability of the monsoon and North African wind regimes, and ties to other orographic flow patterns. Strong modulation of the TGJ by regional processes such as the desert heating cycle, wind convergence at the ITCZ surface front, and the local land–sea breeze cycle are described. Two case studies present the interplay of these influences in detail. The first of these was an “extreme” gap wind event on 12 July, in which horizontal velocities in the Tokar Gap exceeded 26 m s−1 and the flow from the jet extended the full width of the Red Sea basin. This event coincided with development of a large mesoscale convective complex (MCC) and precipitation at the entrance of the Tokar Gap as well as smaller gaps downstream along the Arabian Peninsula. More typical behavior of the TGJ during the 2008 summer is discussed using a second case study on 19 July. Downwind impact of the TGJ is evaluated using Lagrangian model trajectories and analysis of the lateral moisture fluxes (LMFs) during jet events. These results suggest means by which TGJ contributes to large LMFs and has potential bearing upon Sahelian rainfall and MCC development.

scholarly journals The Land‐Sea Breeze of the Red Sea: Observations, Simulations, and Relationships to Regional Moisture Transport

2019 ◽  
Vol 124 (24) ◽  
pp. 13803-13825 ◽  
Author(s):  
Shannon R. Davis ◽  
J. Thomas Farrar ◽  
Robert A. Weller ◽  
Houshuo Jiang ◽  
Lawrence J. Pratt
Keyword(s):  
Red Sea ◽  
Moisture Transport ◽  
Sea Breeze

scholarly journals The influence of sea- and land-breeze circulations on the diurnal variability in precipitation over a tropical island

2017 ◽  
Vol 17 (21) ◽  
pp. 13213-13232 ◽  
Author(s):  
Lei Zhu ◽  
Zhiyong Meng ◽  
Fuqing Zhang ◽  
Paul M. Markowski
Keyword(s):  
Diurnal Variation ◽  
Numerical Simulations ◽  
Diurnal Cycle ◽  
Wrf Model ◽  
Lower Troposphere ◽  
Sea Breeze ◽  
Dominant Factor ◽  
Land Breeze ◽  
Moist Convection ◽  
Diurnal Variability

Abstract. This study examines the diurnal variation in precipitation over Hainan Island in the South China Sea using gauge observations from 1951 to 2012 and Climate Prediction Center MORPHing technique (CMORPH) satellite estimates from 2006 to 2015, as well as numerical simulations. The simulations are the first to use climatological mean initial and lateral boundary conditions to study the dynamic and thermodynamic processes (and the impacts of land–sea breeze circulations) that control the rainfall distribution and climatology. Precipitation is most significant from April to October and exhibits a strong diurnal cycle resulting from land–sea breeze circulations. More than 60 % of the total annual precipitation over the island is attributable to the diurnal cycle with a significant monthly variability. The CMORPH and gauge datasets agree well, except that the CMORPH data underestimate precipitation and have a 1 h peak delay. The diurnal cycle of the rainfall and the related land–sea breeze circulations during May and June were well captured by convection-permitting numerical simulations with the Weather Research and Forecasting (WRF) model, which were initiated from a 10-year average ERA-Interim reanalysis. The simulations have a slight overestimation of rainfall amounts and a 1 h delay in peak rainfall time. The diurnal cycle of precipitation is driven by the occurrence of moist convection around noontime owing to low-level convergence associated with the sea-breeze circulations. The precipitation intensifies rapidly thereafter and peaks in the afternoon with the collisions of sea-breeze fronts from different sides of the island. Cold pools of the convective storms contribute to the inland propagation of the sea breeze. Generally, precipitation dissipates quickly in the evening due to the cooling and stabilization of the lower troposphere and decrease of boundary layer moisture. Interestingly, the rather high island orography is not a dominant factor in the diurnal variation in precipitation over the island.

Impact of Moisture Transport and Boundary Layer Processes on a Very Severe Cyclonic Storm Using the WRF Model

2019 ◽  
Vol 176 (12) ◽  
pp. 5445-5461 ◽  
Author(s):  
S. S. V. S. Ramakrishna ◽  
Nellipudi Nanaji Rao ◽  
B. Ravi Srinivasa Rao ◽  
P. Srinivasa Rao ◽  
C. V. Srinivas ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Moisture Transport ◽  
Wrf Model ◽  
Cyclonic Storm ◽  
Boundary Layer Processes ◽  
Severe Cyclonic Storm

scholarly journals Combinational Optimization of the WRF Physical Parameterization Schemes to Improve Numerical Sea Breeze Prediction Using Micro-Genetic Algorithm

2021 ◽  
Vol 11 (23) ◽  
pp. 11221
Author(s):  
Ji Won Yoon ◽  
Sujeong Lim ◽  
Seon Ki Park
Keyword(s):  
Genetic Algorithm ◽  
Wind Speed ◽  
Land Surface ◽  
Wrf Model ◽  
Longwave Radiation ◽  
Sea Breeze ◽  
Meteorological Variables ◽  
Parameterization Schemes ◽  
Micro Genetic Algorithm ◽  
Physical Parameterization

This study aims to improve the performance of the Weather Research and Forecasting (WRF) model in the sea breeze circulation using the micro-Genetic Algorithm (micro-GA). We found the optimal combination of four physical parameterization schemes related to the sea breeze system, including planetary boundary layer (PBL), land surface, shortwave radiation, and longwave radiation, in the WRF model coupled with the micro-GA (WRF-μGA system). The optimization was performed with respect to surface meteorological variables (2 m temperature, 2 m relative humidity, 10 m wind speed and direction) and a vertical wind profile (wind speed and direction), simultaneously for three sea breeze cases over the northeastern coast of South Korea. The optimized set of parameterization schemes out of the WRF-μGA system includes the Mellor–Yamada–Nakanishi–Niino level-2.5 (MYNN2) for PBL, the Noah land surface model with multiple parameterization options (Noah-MP) for land surface, and the Rapid Radiative Transfer Model for GCMs (RRTMG) for both shortwave and longwave radiation. The optimized set compared with the various other sets of parameterization schemes for the sea breeze circulations showed up to 29 % for the improvement ratio in terms of the normalized RMSE considering all meteorological variables.

scholarly journals Assimilation of Satellite-Derived Soil Moisture for Improved Forecasts of the Great Plains Low-Level Jet

2020 ◽  
Vol 148 (11) ◽  
pp. 4607-4627
Author(s):  
Craig R. Ferguson ◽  
Shubhi Agrawal ◽  
Mark C. Beauharnois ◽  
Geng Xia ◽  
D. Alex Burrows ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Wind Speed ◽  
Data Assimilation ◽  
Great Plains ◽  
Wrf Model ◽  
Added Value ◽  
Low Level ◽  
Convective Systems ◽  
South Central ◽  
Mesoscale Convective

AbstractIn the context of forecasting societally impactful Great Plains low-level jets (GPLLJs), the potential added value of satellite soil moisture (SM) data assimilation (DA) is high. GPLLJs are both sensitive to regional soil moisture gradients and frequent drivers of severe weather, including mesoscale convective systems. An untested hypothesis is that SM DA is more effective in forecasts of weakly synoptically forced, or uncoupled GPLLJs, than in forecasts of cyclone-induced coupled GPLLJs. Using the NASA Unified Weather Research and Forecasting (NU-WRF) Model, 75 GPLLJs are simulated at 9-km resolution both with and without NASA Soil Moisture Active Passive SM DA. Differences in modeled SM, surface sensible (SH) and latent heat (LH) fluxes, 2-m temperature (T2), 2-m humidity (Q2), PBL height (PBLH), and 850-hPa wind speed (W850) are quantified for individual jets and jet-type event subsets over the south-central Great Plains, as well as separately for each GPLLJ sector (entrance, core, and exit). At the GPLLJ core, DA-related changes of up to 5.4 kg m−2 in SM can result in T2, Q2, LH, SH, PBLH, and W850 differences of 0.68°C, 0.71 g kg−2, 59.9 W m−2, 52.4 W m−2, 240 m, and 4 m s−1, respectively. W850 differences focus along the jet axis and tend to increase from south to north. Jet-type differences are most evident at the GPLLJ exit where DA increases and decreases W850 in uncoupled and coupled GPLLJs, respectively. Data assimilation marginally reduces negative wind speed bias for all jets, but the correction is greater for uncoupled GPLLJs, as hypothesized.

scholarly journals Moisture transport from the Arctic: a characterization from a Lagrangian perspective

2018 ◽  
Vol 44 (2) ◽  
pp. 659 ◽  
Author(s):  
M. Vázquez ◽  
R. Nieto ◽  
A. Drumond ◽  
L. Gimeno
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Moisture Transport ◽  
Hydrological Cycle ◽  
Moisture Loss ◽  
Lagrangian Model ◽  
The Arctic ◽  
Sea Ice Extent ◽  
The Arctic Ocean ◽  
Moisture Supply

The Arctic Ocean has suffered extreme reductions in sea ice in recent decades, and these observed changes suggest implications in terms of moisture transport. The Arctic region is a net sink of moisture in terms of the total hydrological cycle, however, its role as a moisture source for specific regions has not been extensively studied. Our results show that 80% of the moisture supply from the Arctic contributes to precipitation over itself, representing about 8% of the global moisture supply to the Arctic, the remaining 20% is distributed in the surrounding. A reduction in the sea ice extent could make the Arctic Ocean a slightly higher source of moisture to itself or to the surrounding areas. The analysis of the areas affected by Arctic moisture transport is important for establishing those areas vulnerable to change in a framework of a growing sea ice decline. To this end, the Lagrangian model FLEXPART was used in this work to establish the main sinks for the Arctic Ocean, focusing on the moisture transport from this region. The results suggest that most of the moisture loss occurs locally over the Arctic Ocean itself, especially in summer. Some moisture contribution from the Arctic Ocean to continental areas in North America and Eurasia is also noted in autumn and winter especially from Central Arctic, the East Siberian Sea, the Laptev, Kara, Barents, East Greenland and Bering Seas, and the Sea of Okhotsk.

scholarly journals Comparing high resolution WRF-VPRM simulations and two global CO<sub>2</sub> transport models with coastal tower measurements of CO<sub>2</sub>

2009 ◽  
Vol 6 (5) ◽  
pp. 807-817 ◽  
Author(s):  
R. Ahmadov ◽  
C. Gerbig ◽  
R. Kretschmer ◽  
S. Körner ◽  
C. Rödenbeck ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Fraction ◽  
Wrf Model ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Concentration Data ◽  
Modeling Tools ◽  
Global Models ◽  
Diurnal Variability ◽  
Resolution Model

Abstract. In order to better understand the effects that mesoscale transport has on atmospheric CO2 distributions, we have used the atmospheric WRF model coupled to the diagnostic biospheric model VPRM, which provides high resolution biospheric CO2 fluxes based on MODIS satellite indices. We have run WRF-VPRM for the period from 16 May to 15 June in 2005 covering the intensive period of the CERES experiment, using the CO2 fields from the global model LMDZ for initialization and lateral boundary conditions. The comparison of modeled CO2 concentration time series against observations at the Biscarosse tower and against output from two global models – LMDZ and TM3 – clearly reveals that WRF-VPRM can capture the measured CO2 signal much better than the global models with lower resolution. Also the diurnal variability of the atmospheric CO2 field caused by recirculation of nighttime respired CO2 is simulated by WRF-VRPM reasonably well. Analysis of the nighttime data indicates that with high resolution modeling tools such as WRF-VPRM a large fraction of the time periods that are impossible to utilize in global models, can be used quantitatively and may help to constrain respiratory fluxes. The paper concludes that we need to utilize a high-resolution model such as WRF-VPRM to use continental observations of CO2 concentration data with more spatial and temporal coverage and to link them to the global inversion models.

Interaction of Urban Heat Island Effects and Land–Sea Breezes during a New York City Heat Event

2020 ◽  
Vol 59 (3) ◽  
pp. 477-495 ◽  
Author(s):  
Timothy J. Bauer
Keyword(s):  
New York ◽  
New York City ◽  
Wrf Model ◽  
Sea Breeze ◽  
Heat Island ◽  
Model Data ◽  
Sea Temperature ◽  
Heat Event ◽  
Urban Heat ◽  
Surface Observations

AbstractThe state of knowledge of the effects of urban heat islands is advanced through investigation of a heat event in the highly complex coastal environment of New York City (NYC) by using the Weather Research and Forecasting (WRF) Model and surface observations in the NYC metropolitan area to evaluate heat retention at high- and low-temperature times during 18–20 July 2013. Urban surface air temperatures are 1°–2°C higher than rural temperatures throughout the daytime and increase to 3°–5°C higher during the night. Lack of a land–sea temperature gradient prevents development of a land breeze during the night. A land–sea temperature difference approaching 20°C leads to sea-breeze effects during 18 July that reduce daytime skin temperatures, but higher winds greatly reduce the sea breeze during 19 July. WRF Model data are generated using three urban parameterization schemes. The most sophisticated multilayer urban parameterization proves to be most accurate when compared with surface observation data. Errors between WRF Model data and surface observations are attributed to assigned coastal sea surface temperatures, excessive building drag, and too little urban heat retention. Adjustments to the input parameters to the multilayer scheme improved accuracy to lead to the control simulation used for urban heat island effects and land–sea-breeze analysis. NYC building interaction with the synoptic flow generates urban drag and wake effects, although relatively high winds limit their extent. Urban flow results and identified model errors support the development and deployment of the best urban parameterization scheme.

Annotated catalogue of beetles (Coleoptera) of the Socotra Archipelago

Zootaxa ◽  
2019 ◽  
Vol 4715 (1) ◽  
pp. 1-76 ◽  
Author(s):  
JIŘÍ HÁJEK ◽  
JAN BEZDĚK
Keyword(s):  
Arabian Peninsula ◽  
Species Level ◽  
East African ◽  
African Species ◽  
Old World ◽  
Tropical Areas ◽  
Annotated Catalogue ◽  
Socotra Archipelago ◽  
Western Palaearctic ◽  
First Time

Beetles of the Socotra Archipelago, Yemen, were catalogued. Altogether, 645 morphospecies from 56 families have been recognised from the Archipelago, of which 516 species (one with an additional two subspecies) were identified to the species level. Twenty-four, mostly widely distributed, species are recorded from the Socotra Archipelago for the first time, and three species are newly recorded for the islands Abd el Kuri (1) and Samha (2). Lithocharis socotrana Assing, 2015 (Staphylinidae), described from Socotra, is recorded from continental Yemen for the first time. Five incomplete or incorrect previous records are corrected. A total of 305 (47%) of all recorded species are considered to be endemic to the Socotra Archipelago. A total of 62 (10%) species are widely distributed Afrotropical species, and 35 (5.5%) East African species, often reaching also the Arabian Peninsula; 16 (2.5%) species occur in the eremial zone of Saharo-Arabian (or Saharo-Sindian) region. Only 14 (2%) species were previously known solely from the Arabian Peninsula; 30 (4.5%) species have cosmopolitan (and often anthropogenic) distributions; 28 (4.5%) species are widely distributed in (sub)tropical areas of the Old World; and 26 (4%) species have a predominantly western Palaearctic distribution. At present, 129 (20%) morphospecies remain unidentified; however, we expect that many of them represent as yet undescribed taxa endemic to the Archipelago. 

Sign in / Sign up

Export Citation Format

Share Document