scholarly journals Modelling the extreme precipitation event over Madeira Island on 20 February 2010

2011 ◽  
Vol 11 (9) ◽  
pp. 2437-2452 ◽  
Author(s):  
T. Luna ◽  
A. Rocha ◽  
A. C. Carvalho ◽  
J. A. Ferreira ◽  
J. Sousa
Keyword(s):  
Extreme Precipitation ◽  
Extreme Event ◽  
Wrf Model ◽  
Weather Conditions ◽  
Horizontal Resolution ◽  
Extreme Precipitation Event ◽  
Cumulus Parameterization ◽  
Precipitation Event ◽  
Madeira Island ◽  
Strong Winds

Abstract. In the morning of the 20 February of 2010 an extreme precipitation event occurred over Madeira Island. This event triggered several flash floods and mudslides in the southern parts of the island, resulting in 42 confirmed deaths, 100 injured, and at least 8 people still missing. These extreme weather conditions were associated to a weather frontal system moving northeastwards embedded in a low pressure area centered in the Azores archipelago. This storm was one in a series of such storms that affected Portugal, Spain, Morocco and the Canary islands causing flooding and strong winds. These storms were bolstered by an unusually strong sea surface temperature gradient across the Atlantic Ocean. In this study, the WRF model is used to evaluate the intensity and predictability of this precipitation extreme event over the island. The synoptic/orographic nature of the precipitation is also evaluated, as well as the sensitivity of the model to horizontal resolution and cumulus parameterization. Orography was found to be the main factor explaining the occurrence, amplitude and phase of precipitation over the Island.

scholarly journals Sensitivity of the WRF model to the lower boundary in an extreme precipitation event – Madeira Island case study

2013 ◽  
Vol 1 (5) ◽  
pp. 5603-5641 ◽  
Author(s):  
J. C. Teixeira ◽  
A. C. Carvalho ◽  
T. Luna ◽  
A. Rocha
Keyword(s):  
Land Use ◽  
Extreme Precipitation ◽  
Lower Boundary ◽  
Wrf Model ◽  
Forecast Model ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Test Case ◽  
Madeira Island

Abstract. Through the years, the advances in satellite technology made feasible the acquisition of information about the Earth surface, such as elevation and land use with great detail and resolution. This information can be included in numerical atmospheric models, updating them and providing a more detailed lower boundary, which in turn can improve the results of events forced by it. Given this, this work aims to study the sensitivity of the Weather Research and Forecast model to three different topography datasets as well as two different land use datasets in an extreme precipitation event. A test case study in which topography driven precipitation was dominant over Madeira Island was considered which triggered several flash floods and mudslides in the southern parts of the island. Model results show higher model skill in precipitation over Madeira leeward and in the windward wind flow, in spite of the non significant enhancement on the overall results with higher resolution datasets of topography and land use.

How Well Can a Climate Model Simulate an Extreme Precipitation Event: A Case Study Using the Transpose-AMIP Experiment

2018 ◽  
Vol 31 (16) ◽  
pp. 6543-6556 ◽  
Author(s):  
Jian Li ◽  
Haoming Chen ◽  
Xinyao Rong ◽  
Jingzhi Su ◽  
Yufei Xin ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Heavy Rainfall ◽  
Climate Model ◽  
Extreme Event ◽  
Spatial Scales ◽  
Precipitation Amount ◽  
Temporal Distribution ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Climate System Model

A high-impact extreme precipitation event over the Yangtze River valley (YRV) in the midsummer of 2016 is simulated using the Climate System Model of Chinese Academy of Meteorological Sciences (CAMS-CSM). After validation of the model’s capability in reproducing the climatological features of precipitation over the YRV, the Transpose Atmospheric Model Intercomparison Project (T-AMIP)–type experiment, which runs the climate model in the weather forecast mode, is applied to investigate the performance of the climate model in simulating the spatial and temporal distribution of rainfall and the related synoptic circulation. Analyses of T-AMIP results indicate that the model realistically reproduces the heavy rainfall centers of accumulated precipitation amount along the YRV, indicating that the climate model has the ability to simulate the severity of the extreme event. However, the frequency–intensity structure shows similar biases as in the AMIP experiment, especially the underestimation of the maximum hourly intensity. The simulation of two typical heavy rainfall periods during the extreme event is further evaluated. The results illustrate that the model shows different performances during periods dominated by circulation systems of different spatial scales. The zonal propagation of heavy rainfall centers during the first two days, which is related to the eastward movement of the southwest vortex, is well reproduced. However, for another period with a smaller vortex, the model produces an artificial steady heavy rainfall center over the upwind slope of the mountains rather than the observed eastward movement of the precipitation centers.

scholarly journals Sensitivity of the WRF model to the lower boundary in an extreme precipitation event – Madeira island case study

2014 ◽  
Vol 14 (8) ◽  
pp. 2009-2025 ◽  
Author(s):  
J. C. Teixeira ◽  
A. C. Carvalho ◽  
M. J. Carvalho ◽  
T. Luna ◽  
A. Rocha
Keyword(s):  
Land Use ◽  
Extreme Precipitation ◽  
Layer Structure ◽  
Lower Boundary ◽  
Wrf Model ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Test Case ◽  
Data Sets ◽  
Difference Fields

Abstract. The advances in satellite technology in recent years have made feasible the acquisition of high-resolution information on the Earth's surface. Examples of such information include elevation and land use, which have become more detailed. Including this information in numerical atmospheric models can improve their results in simulating lower boundary forced events, by providing detailed information on their characteristics. Consequently, this work aims to study the sensitivity of the weather research and forecast (WRF) model to different topography as well as land-use simulations in an extreme precipitation event. The test case focused on a topographically driven precipitation event over the island of Madeira, which triggered flash floods and mudslides in the southern parts of the island. Difference fields between simulations were computed, showing that the change in the data sets produced statistically significant changes to the flow, the planetary boundary layer structure and precipitation patterns. Moreover, model results show an improvement in model skill in the windward region for precipitation and in the leeward region for wind, in spite of the non-significant enhancement in the overall results with higher-resolution data sets of topography and land use.

scholarly journals Hydro-meteorologic Assessment of October 2015 Extreme Precipitation Event on Santee Experimental Forest Watersheds, South Carolina

2016 ◽  
pp. 19-30 ◽  
Author(s):  
Devendra M. Amatya ◽  
Charles A. Harrison ◽  
Carl C. Trettin
Keyword(s):  
South Carolina ◽  
Extreme Precipitation ◽  
Land Surface ◽  
Extreme Event ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Storm Events ◽  
Maximum Rainfall ◽  
Natural Resource Conservation Service ◽  
Peak Flood

The extreme precipitation event on October 3-4, 2015, likely resulting from the convergence of a persistent deep easterly flow, the continuous supply of moisture, the terrain, and the circulation associated with Hurricane Joaquin off the eastern Atlantic Coast (http://cms.met.psu. edu/sref/severe/2015/04Oct2015.pdf) resulted in extreme and prolonged flooding in many parts of South Carolina. We present the precipitation amounts and intensities observed at four gauges on the USDA Forest Service Santee Experimental Forest (SEF) watersheds during this extreme event in conjunction with the antecedent conditions for 5 days prior to the event. All four rain gauges recorded 24-hr maximum rainfall of 340 mm or more during October 3-4, exceeding the Natural Resource Conservation Service (NRCS) 100-yr 24-hr design rainfall data. The 5-day antecedent measured rainfall prior to October 3 already exceeded 170 mm in three of the four gauges resulting in weekly (September 28-October 4 totals exceeding 625 mm in all gauges. Local surface water ponding of as much as 0.46 m above land surface was observed on one of the groundwater wells at an elevation of 10.395 m. The recorded stage heights at one 1st order (WS 80) and one- 2nd order (WS79) watershed gauging stations over topped the compound weir (WS 80) and weir/culvert (WS 79) outlets, with the highest stages coming near the invert of the bridge above the weir gauges and inundating large riparian areas upstream of them. Preliminary calculations yielded peak flood discharges of at least 17.4 m3 s-1 (10.9 m3 s-1 km-2 or 996 cfs/mi2) and 33.9 m3 s-1 (6.8 m3 s-1 km-2 or 620 cfs/mi2) for a 1st and 2nd order watersheds, respectively. These values exceeded the previously measured peak discharges within a 25-year record of 3.8 m3 s-1 and 11.2 m3 s-1 for these two watersheds that were recorded on October 24, 2008. When compared with computed design discharges the estimated peak flood discharges on October 4, 2015 exceed the values for a 500-yr return period. These extreme peak flood discharge results may provide insights for a need to revisit existing approaches for hydrologic analyses and design of cross drainage and other water management structures as concerns about extreme storm events resulting from global warming continue.

scholarly journals Assimilating X- and S-Band Radar Data for a Heavy Precipitation Event in Italy

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1727
Author(s):  
Valerio Capecchi ◽  
Andrea Antonini ◽  
Riccardo Benedetti ◽  
Luca Fibbi ◽  
Samantha Melani ◽  
...  
Keyword(s):  
Extreme Event ◽  
Wrf Model ◽  
Heavy Precipitation ◽  
Radar Data ◽  
Flash Floods ◽  
Precipitation Event ◽  
Weather Research And Forecasting ◽  
Limited Area ◽  
Heavy Precipitation Event ◽  
The Town

During the night between 9 and 10 September 2017, multiple flash floods associated with a heavy-precipitation event affected the town of Livorno, located in Tuscany, Italy. Accumulated precipitation exceeding 200 mm in two hours was recorded. This rainfall intensity is associated with a return period of higher than 200 years. As a consequence, all the largest streams of the Livorno municipality flooded several areas of the town. We used the limited-area weather research and forecasting (WRF) model, in a convection-permitting setup, to reconstruct the extreme event leading to the flash floods. We evaluated possible forecasting improvements emerging from the assimilation of local ground stations and X- and S-band radar data into the WRF, using the configuration operational at the meteorological center of Tuscany region (LaMMA) at the time of the event. Simulations were verified against weather station observations, through an innovative method aimed at disentangling the positioning and intensity errors of precipitation forecasts. A more accurate description of the low-level flows and a better assessment of the atmospheric water vapor field showed how the assimilation of radar data can improve quantitative precipitation forecasts.

scholarly journals Response of a mixed grass prairie to an extreme precipitation event

Ecosphere ◽  
2015 ◽  
Vol 6 (10) ◽  
pp. art172 ◽  
Author(s):  
Amy L. Concilio ◽  
Janet S. Prevéy ◽  
Peter Omasta ◽  
James O'Connor ◽  
Jesse B. Nippert ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Mixed Grass Prairie ◽  
Mixed Grass

A parameterization of slantwise convection in the WRF model

2021 ◽  
Author(s):  
Ting-Chen Chen ◽  
Man-Kong Yau ◽  
Daniel J. Kirshbaum
Keyword(s):  
General Circulation ◽  
Wrf Model ◽  
Real Data ◽  
General Circulation Models ◽  
Added Value ◽  
Cumulus Parameterization ◽  
Moisture Loss ◽  
Precipitation Event ◽  
Cyclonic Storm ◽  
Slantwise Convection

Abstract In this study, we introduce a parameterization scheme for slantwise convection (SC) to be considered for models that are too coarse to resolve slantwise convection explicitly (with a horizontal grid spacing coarser than 15 km or less). This SC scheme operates in a locally defined 2D cross-section perpendicular to the deep-layer-averaged thermal wind. It applies momentum tendency to adjust the environment toward slantwise neutrality with a prescribed adjustment timescale. Condensational heating and the associated moisture loss are also considered. To evaluate the added value of the SC scheme, we implement it in the Weather Research and Forecasting (WRF) model to supplement the existing cumulus parameterization schemes for upright convection and test for two different numerical setups: a 2D idealized, unforced release of conditional symmetric instability (CSI) in an initially conditionally stable environment, and a 3D real-data precipitation event containing both CSI and conditional instability along the cold front of a cyclonic storm near the UK. Both test cases show significant improvements for the coarse-gridded (40-km) simulations when parameterizing slantwise convection. Compared to the 40-km simulations with only the upright convection scheme, the counterparts with the additional SC scheme exhibit a larger extent of CSI neutralization, generate a stronger grid-resolved slantwise circulation, and produce greater amounts of precipitation, all in better agreement with the corresponding fine-gridded reference simulations. Given the importance of slantwise convection in midlatitude weather systems, our results suggest that there exist potential benefits of parameterizing slantwise convection in general circulation models.

scholarly journals Polarimetric Radar Signatures and Performance of Various Radar Rainfall Estimators during an Extreme Precipitation Event over the Thousand-Island Lake Area in Eastern China

2019 ◽  
Vol 11 (20) ◽  
pp. 2335 ◽  
Author(s):  
Yabin Gou ◽  
Haonan Chen ◽  
Jiafeng Zheng
Keyword(s):  
Extreme Precipitation ◽  
Rapid Development ◽  
Eastern China ◽  
Rain Gauge ◽  
Extreme Precipitation Event ◽  
Precipitation Event ◽  
Distribution Data ◽  
Lake Area ◽  
Polarimetric Radar ◽  
Radar Rainfall

Polarimetric radar provides more choices and advantages for quantitative precipitation estimation (QPE) than single-polarization radar. Utilizing the C-band polarimetric radar in Hangzhou, China, six radar QPE estimators based on the horizontal reflectivity (ZH), specific attenuation (AH), specific differential phase (KDP), and double parameters that further integrate the differential reflectivity (ZDR), namely, R(ZH, ZDR), R(KDP, ZDR), and R(AH, ZDR), are investigated for an extreme precipitation event that occurred in Eastern China on 1 June 2016. These radar QPE estimators are respectively evaluated and compared with a local rain gauge network and drop size distribution data observed by two disdrometers. The results show that (i) although R(AH, ZDR) underestimates in the light rain scenario, it performs the best among all radar QPE estimators according to the normalized mean error; (ii) the optimal radar rainfall relationship and consistency between radar measurements aloft and their surface counterparts are both required to obtain accurate rainfall estimates close to the ground. The contamination from melting layer on AH and KDP can make R(AH), R(AH, ZDR), R(KDP), and R(KDP, ZDR) less effective than R(ZH) and R(ZH,ZDR). Instead, adjustments of the α coefficient can partly reduce such impact and hence render a superior AH–based rainfall estimator; (iii) each radar QPE estimator may outperform others during some time intervals featured by particular rainfall characteristics, but they all tend to underestimate rainfall if radar fails to capture the rapid development of rainstorms.

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