High-resolution numerical modelling of convective precipitation over Northern Italy

Abstract. With the aim of improving resilience to flooding and increasing preparedness to face levee-breach-induced inundations, this paper presents a methodology for creating a wide database of numerically simulated flooding scenarios due to embankment failures, applicable to any lowland area protected by river levees. The analysis of the detailed spatial and temporal flood data obtained from these hypothetical scenarios is expected to contribute both to the development of civil protection planning and to immediate actions during a possible future flood event (comparable to one of the available simulations in the database) for which real-time modelling may not be feasible. The most relevant criteria concerning the choice of mathematical model, grid resolution, hydrological conditions, breach parameters and locations are discussed in detail. The proposed methodology, named RESILIENCE, is applied to a 1100 km2 pilot area in northern Italy. The creation of a wide database for the study area is made possible thanks to the adoption of a GPU-accelerated shallow-water numerical model which guarantees remarkable computational efficiency (ratios of physical to computational time up to 80) even for high-resolution meshes (2.5–5 m) and very large domains (>1000 km2).

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Seasonal monitoring and estimation of regional aerosol distribution over Po valley, northern Italy, using a high-resolution MAIAC product

Atmospheric Environment ◽

10.1016/j.atmosenv.2016.06.037 ◽

2016 ◽

Vol 141 ◽

pp. 106-121 ◽

Cited By ~ 17

Author(s):

Barbara Arvani ◽

R. Bradley Pierce ◽

Alexei I. Lyapustin ◽

Yujie Wang ◽

Grazia Ghermandi ◽

...

Keyword(s):

High Resolution ◽

Northern Italy ◽

Po Valley ◽

Aerosol Distribution ◽

Seasonal Monitoring

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Improving Numerical Weather Predictions of Summertime Precipitation over the Southeastern United States through a High-Resolution Initialization of the Surface State

Weather and Forecasting ◽

10.1175/2011waf2222455.1 ◽

2011 ◽

Vol 26 (6) ◽

pp. 785-807 ◽

Cited By ~ 35

Author(s):

Jonathan L. Case ◽

Sujay V. Kumar ◽

Jayanthi Srikishen ◽

Gary J. Jedlovec

Keyword(s):

United States ◽

Soil Moisture ◽

High Resolution ◽

Land Surface ◽

Weather Prediction ◽

Southeastern United States ◽

Model Verification ◽

Sea Surface ◽

Convective Precipitation ◽

Numerical Weather

Abstract It is hypothesized that high-resolution, accurate representations of surface properties such as soil moisture and sea surface temperature are necessary to improve simulations of summertime pulse-type convective precipitation in high-resolution models. This paper presents model verification results of a case study period from June to August 2008 over the southeastern United States using the Weather Research and Forecasting numerical weather prediction model. Experimental simulations initialized with high-resolution land surface fields from the National Aeronautics and Space Administration’s (NASA) Land Information System (LIS) and sea surface temperatures (SSTs) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) are compared to a set of control simulations initialized with interpolated fields from the National Centers for Environmental Prediction’s (NCEP) 12-km North American Mesoscale model. The LIS land surface and MODIS SSTs provide a more detailed surface initialization at a resolution comparable to the 4-km model grid spacing. Soil moisture from the LIS spinup run is shown to respond better to the extreme rainfall of Tropical Storm Fay in August 2008 over the Florida peninsula. The LIS has slightly lower errors and higher anomaly correlations in the top soil layer but exhibits a stronger dry bias in the root zone. The model sensitivity to the alternative surface initial conditions is examined for a sample case, showing that the LIS–MODIS data substantially impact surface and boundary layer properties. The Developmental Testbed Center’s Meteorological Evaluation Tools package is employed to produce verification statistics, including traditional gridded precipitation verification and output statistics from the Method for Object-Based Diagnostic Evaluation (MODE) tool. The LIS–MODIS initialization is found to produce small improvements in the skill scores of 1-h accumulated precipitation during the forecast hours of the peak diurnal convective cycle. Because there is very little union in time and space between the forecast and observed precipitation systems, results from the MODE object verification are examined to relax the stringency of traditional gridpoint precipitation verification. The MODE results indicate that the LIS–MODIS-initialized model runs increase the 10 mm h−1 matched object areas (“hits”) while simultaneously decreasing the unmatched object areas (“misses” plus “false alarms”) during most of the peak convective forecast hours, with statistically significant improvements of up to 5%. Simulated 1-h precipitation objects in the LIS–MODIS runs more closely resemble the observed objects, particularly at higher accumulation thresholds. Despite the small improvements, however, the overall low verification scores indicate that much uncertainty still exists in simulating the processes responsible for airmass-type convective precipitation systems in convection-allowing models.

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Evaluating multi-scale precipitation forecasts using high resolution analysis

Advances in Science and Research ◽

10.5194/asr-4-89-2010 ◽

2010 ◽

Vol 4 (1) ◽

pp. 89-98 ◽

Cited By ~ 8

Author(s):

C. Wittmann ◽

T. Haiden ◽

A. Kann

Keyword(s):

High Resolution ◽

Deep Convection ◽

Convective Precipitation ◽

Structure Amplitude ◽

Subjective Impression ◽

Mean Values ◽

High Resolution Analysis ◽

Resolution Analysis ◽

High Impact Weather ◽

The Individual

Abstract. The SAL (Structure, Amplitude, Location) method is used for verification of precipitation forecasts at horizontal grid spacings ranging from 2.5 km to 25 km, using a high-resolution 1 km precipitation analysis as a reference. The verification focuses on a summertime period with predominantly convective precipitation. The verification domain contains lowland as well as alpine areas. Evaluation of the individual SAL components shows that with regard to area mean values (A) the benefit of high resolutions models becomes apparent only in high impact weather situations. For the summertime period studied, the subjective impression of better structured precipitation fields (S) in higher resolution models can generally be confirmed. The most significant improvement appears to be associated with explicit simulation of deep convection.

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Multidecadal Evaluation of WRF Downscaling Capabilities over Western Australia in Simulating Rainfall and Temperature Extremes

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-14-0212.1 ◽

2015 ◽

Vol 54 (2) ◽

pp. 370-394 ◽

Cited By ~ 17

Author(s):

Julia Andrys ◽

Thomas J. Lyons ◽

Jatin Kala

Keyword(s):

High Resolution ◽

Western Australia ◽

General Circulation ◽

Regional Climate ◽

Wrf Model ◽

Climate Extremes ◽

Convective Precipitation ◽

Climate Simulation ◽

Climate Indices ◽

Climate Simulations

AbstractThe authors evaluate a 30-yr (1981–2010) Weather Research and Forecast (WRF) Model regional climate simulation over the southwest of Western Australia (SWWA), a region with a Mediterranean climate, using ERA-Interim boundary conditions. The analysis assesses the spatial and temporal characteristics of climate extremes, using a selection of climate indices, with an emphasis on metrics that are relevant for forestry and agricultural applications. Two nested domains at 10- and 5-km resolution are examined, with the higher-resolution simulation resolving convection explicitly. Simulation results are compared with a high-resolution, gridded observational dataset that provides daily rainfall, minimum temperatures, and maximum temperatures. Results show that, at both resolutions, the model is able to simulate the daily, seasonal, and annual variation of temperature and precipitation well, including extreme events. The higher-resolution domain displayed significant performance gains in simulating dry-season convective precipitation, rainfall around complex terrain, and the spatial distribution of frost conditions. The high-resolution domain was, however, influenced by grid-edge effects in the southwestern margin, which reduced the ability of the domain to represent frontal rainfall along the coastal region. On the basis of these results, the authors feel confident in using the WRF Model for regional climate simulations for the SWWA, including studies that focus on the spatial and temporal representation of climate extremes. This study provides a baseline climatological description at a high resolution that can be used for impact studies and will also provide a benchmark for climate simulations driven by general circulation models.

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Forecasting the evolution in the mixing regime of a deep subalpine lake under climate change scenarios through numerical modelling (Lake Maggiore, Northern Italy/Southern Switzerland)

Climate Dynamics ◽

10.1007/s00382-018-4094-6 ◽

2018 ◽

Vol 51 (9-10) ◽

pp. 3521-3536 ◽

Cited By ~ 14

Author(s):

Andrea Fenocchi ◽

Michela Rogora ◽

Stefano Sibilla ◽

Marzia Ciampittiello ◽

Claudia Dresti

Keyword(s):

Climate Change ◽

Numerical Modelling ◽

Northern Italy ◽

Climate Change Scenarios ◽

Lake Maggiore ◽

Subalpine Lake ◽

Mixing Regime

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Statistical Characteristics of Long-Term High-Resolution Precipitable Water Vapor Data at Darwin

Advances in Data Science and Adaptive Analysis ◽

10.1142/s2424922x18500109 ◽

2018 ◽

Vol 10 (04) ◽

pp. 1850010

Author(s):

Kimberly Leung ◽

Aneesh C. Subramanian ◽

Samuel S. P. Shen

Keyword(s):

Water Vapor ◽

High Resolution ◽

Southern Oscillation ◽

Precipitable Water ◽

Precipitable Water Vapor ◽

Statistical Characteristics ◽

Convective Precipitation ◽

Data Set ◽

Best Estimates

This paper studies the statistical characteristics of a unique long-term high-resolution precipitable water vapor (PWV) data set at Darwin, Australia, from 12 March 2002 to 28 February 2011. To understand the convective precipitation processes for climate model development, the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) program made high-frequency radar observations of PWV at the Darwin ARM site and released the best estimates from the radar data retrievals for this time period. Based on the best estimates, we produced a PWV data set on a uniform 20-s time grid. The gridded data were sufficient to show the fractal behavior of precipitable water with Hausdorff dimension equal to 1.9. Fourier power spectral analysis revealed modulation instability due to two sideband frequencies near the diurnal cycle, which manifests as nonlinearity of an atmospheric system. The statistics of PWV extreme values and daily rainfall data show that Darwin’s PWV has El Nino Southern Oscillation (ENSO) signatures and has potential to be a predictor for weather forecasting. The right skewness of the PWV data was identified, which implies an important property of tropical atmosphere: ample capacity to hold water vapor. The statistical characteristics of this long-term high-resolution PWV data will facilitate the development and validation of climate models, particularly stochastic models.

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