scholarly journals Analysis of intense rainfall events on Madeira Island during the 2009/2010 winter

2012 ◽  
Vol 12 (7) ◽  
pp. 2225-2240 ◽  
Author(s):  
F. T. Couto ◽  
R. Salgado ◽  
M. J. Costa
Keyword(s):  
Precipitable Water ◽  
Heavy Precipitation ◽  
Rain Gauge ◽  
Horizontal Resolution ◽  
Pressure System ◽  
Orographic Effects ◽  
Madeira Island ◽  
High Rainfall ◽  
High Precipitation Events ◽  
Precipitation Events

Abstract. This paper constitutes a step towards the understanding of some characteristics associated with high rainfall amounts and flooding on Madeira Island. The high precipitation events that occurred during the winter of 2009/2010 have been considered with three main goals: to analyze the main atmospheric characteristics associated with the events; to expand the understanding of the interaction between the island and the atmospheric circulations, mainly the effects of the island on the generation or intensification of orographic precipitation; and to evaluate the performance of high resolution numerical modeling in simulating and forecasting heavy precipitation events over the island. The MESO-NH model with a horizontal resolution of 1 km is used, as well as rain gauge data, synoptic charts and measurements of precipitable water obtained from the Atmospheric InfraRed Sounder (AIRS). The results confirm the influence of the orographic effects on precipitation over Madeira as well as the tropical–extratropical interaction, since atmospheric rivers were detected in six out of the seven cases analyzed, acting as a low level moisture supplier, which together with the orographic lifting induced the high rainfall amounts. Only in one of the cases the presence of a low pressure system was identified over the archipelago.

Advances in knowledge 10 years after the torrential rains in Madeira Island (Portugal)

2020 ◽  
Author(s):  
Rui Salgado ◽  
Flavio T. Couto ◽  
Maria Joao Costa
Keyword(s):  
Large Scale ◽  
Precipitable Water ◽  
Heavy Precipitation ◽  
Atmospheric Conditions ◽  
Orographic Effects ◽  
Madeira Island ◽  
Significant Events ◽  
First Case ◽  
Rainfall Patterns ◽  
Tropical Moisture

<p>On February 20, 2010, Madeira island was affected by a tragic event of extreme precipitation. The event was marked by huge economical damage estimated in millions of euros, and more than 40 deaths. Before the event, there were not many studies about severe precipitation in Madeira, which were highly motivated after 2010. This work intent is to show some advancements in knowledge of heavy precipitation events (HPE) in Madeira found in the last decade. The Meso-NH model was used with a rather complete parametrization package of several physical processes occurring in the atmosphere and configured into different dimensions. In order to explore the meridional water vapour transport, the total precipitable water field was extracted from the Atmospheric Infrared Sounder (AIRS) data products. In the first set of simulations, the experiments were performed with three horizontal nested domains (9 km, 3 km, and 1 km resolution). The results for the winter 2009-2010 raised two questions about the topic. First, associated with the large scale environment, and the second one linked to orographic effects. In the first case, apart from a cyclone affecting the island, it was identified the presence of atmospheric rivers (ARs) coupled to frontal systems transporting tropical moisture toward the island. For the orographic effects, the simulations at 1km resolution showed maximums of accumulated precipitation in the highlands. Subsequently, the analysis of the precipitation in Madeira highlands over a 10-year period showed dry summers and the highest rainfall amounts in the winters, although with some significant events occurring also in autumn and spring seasons. Furthermore, it was found that tropical moisture transported through the ARs may reach the island with different intensities and orientation during the winter seasons. However, for the 10 winter periods, the ARs were not the sole factor producing HPE in Madeira. In the second set of simulations, the model was configured with a larger domain of 2.5 km resolution and an inner domain of 0.5 km resolution. All the significant events in autumn 2012 were simulated confirming the orographic effect in the accumulated precipitation. The most interesting result found was the occurrence of maximums values in different regions over the island. For example, over the highlands in the central peaks and southern/northern slopes, or in the coastal plain at lowlands. From the simulations it was possible to explain the causes for the distinct rainfall patterns, and the atmospheric environments associated. The variations in the configuration of the ambient flow, jointly with the orographic forcing may produce convection in distinct regions of the island, resulting in different rainfall patterns. Ten years later, the advances in the understanding of significant precipitation in the Madeira is evident. The results show how different events may occur, since the formation or enhancement of the precipitation over the island is totally dependent on the geographic aspects and atmospheric conditions associated with each precipitating event.</p>

scholarly journals Increasing frequencies and changing characteristics of heavy precipitation events threatening infrastructure in Europe under climate change

2017 ◽  
Vol 17 (7) ◽  
pp. 1177-1190 ◽  
Author(s):  
Katrin M. Nissen ◽  
Uwe Ulbrich
Keyword(s):  
Climate Change ◽  
Regional Climate ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
European Regions ◽  
Event Duration ◽  
Novel Technique ◽  
Climate Simulations ◽  
Daily Events ◽  
Precipitation Events

Abstract. The effect of climate change on potentially infrastructure-damaging heavy precipitation events in Europe is investigated in an ensemble of regional climate simulations conducted at a horizontal resolution of 12 km. Based on legislation and stakeholder interviews the 10-year return period is used as a threshold for the detection of relevant events. A novel technique for the identification of heavy precipitation events is introduced. It records not only event frequency but also event size, duration and severity (a measure taking duration, size and rain amount into account) as these parameters determine the potential consequences of the event. Over most of Europe the frequency of relevant heavy precipitation events is predicted to increase with increasing greenhouse gas concentrations. The number of daily and multi-day events increases at a lower rate than the number of sub-daily events. The event size is predicted to increase in the future over many European regions, especially for sub-daily events. Moreover, the most severe events were detected in the projection period. The predicted changes in frequency, size and intensity of events may increase the risk for infrastructure damages. The climate change simulations do not show changes in event duration.

scholarly journals Precipitation over Monsoon Asia: A Comparison of Reanalyses and Observations

2017 ◽  
Vol 30 (2) ◽  
pp. 465-476 ◽  
Author(s):  
Andrej Ceglar ◽  
Andrea Toreti ◽  
Gianpaolo Balsamo ◽  
Shinya Kobayashi
Keyword(s):  
Temporal Evolution ◽  
Heavy Precipitation ◽  
Rain Gauge ◽  
Rain Gauge Data ◽  
Monsoon Asia ◽  
Spatial Performance ◽  
The World ◽  
Gauge Data ◽  
Source Of Information ◽  
Precipitation Events

Reanalysis products represent a valuable source of information for different impact modeling and monitoring activities over regions with sparse observational data. It is therefore essential to evaluate their behavior and their intrinsic uncertainties. This study focuses on precipitation over monsoon Asia, a key agricultural region of the world. Four reanalysis datasets are evaluated, namely ERA-Interim, ERA-Interim/Land, AgMERRA (an agricultural version of MERRA), and JRA-55. APHRODITE and the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) dataset are the two gridded observational datasets used for the evaluation; the former is based on rain gauge data and the latter on a combination of satellite and rain gauge data. Differences in seasonality, moderate-to-heavy precipitation events, daily distribution, and drought characteristics are analyzed. Results show remarkable differences between the APHRODITE and CHIRPS observational datasets as well as between these datasets and the reanalyses. AgMERRA generally achieves the best performance, but it is not updated at near–real time. ERA-Interim/Land shows good spatial performance, but when the interest is on the temporal evolution JRA-55 is recommended, as it exhibits the most stable temporal behavior. This study shows that the use of reanalyses for impact modeling and monitoring over monsoon Asia requires an accurate evaluation and choices to be tailored to the specific needs.

scholarly journals Assimilation of GNSS tomography products into WRF using radio occultation data assimilation operator

2019 ◽  
Author(s):  
Natalia Hanna ◽  
Estera Trzcina ◽  
Gregor Möller ◽  
Witold Rohm ◽  
Robert Weber
Keyword(s):  
Standard Deviation ◽  
Data Assimilation ◽  
Radio Occultation ◽  
Weather Forecasting ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
Global Navigation Satellite Systems ◽  
Total Delay ◽  
Water Vapour Content ◽  
Precipitation Events

Abstract. From Global Navigation Satellite Systems (GNSS) signals, accurate and high-frequency atmospheric parameters can be determined in all-weather conditions. GNSS tomography is a novel technique that takes advantage of these parameters, especially of slant troposphere observations between GNSS receivers and satellites, traces these signals through a 3D grid of voxels and estimates by an inversion process the refractivity of the water vapour content within each voxel. In the last years, the GNSS tomography development focused on numerical methods to stabilize the solution, which has been achieved to a great extent. Currently, we are facing new challenges and possibilities in the application of GNSS tomography in numerical weather forecasting – the main research objective of this paper. In the first instance, refractivity fields were estimated using two different GNSS tomography models (TUW, WUELS), which cover the area of Central Europe during the period of 29 May–14 June 2013, when heavy precipitation events were observed. For both models, Slant Wet Delays (SWD) were calculated based on estimates of Zenith Total Delay (ZTD) and horizontal gradients, provided for 72 GNSS sites by Geodetic Observatory Pecny (GOP). In total, three sets of SWD observations were tested (set0 without compensation for hydrostatic anisotropic effects, set1 with compensation of this effect, set2 cleaned by wet delays outside the inner voxel model). The GNSS tomography outputs have been assimilated into the nested (12- and 36-km horizontal resolution) Weather Research and Forecasting (WRF) model, using its three-dimensional variational data assimilation (WRFDA 3DVar) system, in particular its radio occultation observations operator (GPSREF). As only total refractivity is assimilated in GPSREF, it was calculated as the sum of the hydrostatic part derived from the ALADIN-CZ model and the wet part from the GNSS tomography. We compared the results of the GNSS tomography data assimilation to the radiosonde (RS) observations. The validation shows the improvement in the weather forecasting of relative humidity (bias, standard deviation) and temperature (standard deviation) during heavy precipitation events. Future improvements to the assimilation method are also discussed.

A Real-Time Algorithm to Identify Convective Precipitation Adjacent to or within the Bright Band in the Radar Scan Domain

2021 ◽  
Vol 22 (5) ◽  
pp. 1139-1151
Author(s):  
Zhe Zhang ◽  
Youcun Qi ◽  
Donghuan Li ◽  
Ziwei Zhu ◽  
Meilin Yang ◽  
...  
Keyword(s):  
Heavy Precipitation ◽  
Rain Gauge ◽  
Polar Coordinates ◽  
Convective Precipitation ◽  
Horizontal Gradient ◽  
Bright Band ◽  
Stratiform Region ◽  
Hydrological Hazards ◽  
Stratiform Precipitation ◽  
Precipitation Events

AbstractHydrological hazards usually occur after heavy precipitation, especially during strong convection. Therefore, accurately identifying convective precipitation is very helpful for hydrological warning and forecasting. However, separating the convective, bright band (BB), and stratiform precipitation is found to be challenging when the convection is adjacent to or within the BB region. A new convection/BB/stratiform precipitation segregation algorithm is proposed in this study to resolve this challenging issue. This algorithm is applicable for a single radar volume scan data in native (polar) coordinates and consists of four processes: 1) check the freezing (0°C) level to roughly assess whether convection is occurring or not; 2) identify the convective cores through analyzing composite reflectivity (maximum reflectivity for a given range gate among all the sweeps), vertically integrated liquid water (VIL), VIL horizontal gradient, and reflectivity at the levels of 0°, −10°, and above −10°C; 3) delineate the whole convective region through the seeded region growing method by taking account of the microphysical differences between the BB and convective regions; and 4) delineate BB features in the stratiform region. The proposed algorithm utilizes the physical characteristics of different precipitation types for precisely segregating the convective, BB, and stratiform precipitation. This algorithm has been tested with radar data of different precipitation events and evaluated with three months of rain gauge data. The results show that the proposed algorithm performs consistently well for challenging precipitation events with the convection adjacent to or within a strong BB. Furthermore, the proposed algorithm could be used to improve the vertical profile of reflectivity (VPR) correction and reduce the overestimation of rainfall in the BB precipitation region.

Prediction of daily heavy precipitation in a lowland area using GPS and surface weather data

2008 ◽  
Vol 8 (1) ◽  
pp. 101-106
Author(s):  
Makito Mori ◽  
Kazuaki Hiramatsu ◽  
Masayoshi Harada
Keyword(s):  
Water Vapor ◽  
Meteorological Data ◽  
Precipitable Water ◽  
Heavy Precipitation ◽  
Daily Basis ◽  
Weather Data ◽  
Surface Weather ◽  
Lowland Area ◽  
Infinite Height ◽  
Precipitation Events

Recent progress in GPS technology has enabled us to estimate the total amount of water vapor in an atmospheric column with infinite height as ’GPS-derived precipitable water vapor’ (GPS-PWV). In the present study, we analyzed the GPS and meteorological data obtained in Saga Plain, in northern Kyushu, Japan. An attempt was made to predict heavy precipitation (≥50 mm d−1) on a daily basis using the analyzed relations between surface temperature and GPS-PWV. Several features were revealed that were associated with the daily heavy precipitation at the study area. An index was made to predict heavy precipitation on a daily basis. Applying the index to observations, we obtained acceptable results of the prediction. It is suggested that GPS is useful for predicting heavy precipitation events.

scholarly journals Modelling Mediterranean heavy precipitation events at climate scale: an object-oriented evaluation of the CNRM-AROME convection-permitting regional climate model

2021 ◽  
Author(s):  
Cécile Caillaud ◽  
Samuel Somot ◽  
Antoinette Alias ◽  
Isabelle Bernard-Bouissières ◽  
Quentin Fumière ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Object Oriented ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
Added Value ◽  
Continuous Simulation ◽  
Climate Scale ◽  
Precipitation Events

AbstractModelling the rare but high-impact Mediterranean Heavy Precipitation Events (HPEs) at climate scale remains a largely open scientific challenge. The issue is adressed here by running a 38-year-long continuous simulation of the CNRM-AROME Convection-Permitting Regional Climate Model (CP-RCM) at a 2.5 km horizontal resolution and over a large pan-Alpine domain. First, the simulation is evaluated through a basic Eulerian statistical approach via a comparison with selected high spatial and temporal resolution observational datasets. Northwestern Mediterranean fall extreme precipitation is correctly represented by CNRM-AROME at a daily scale and even better at an hourly scale, in terms of location, intensity, frequency and interannual variability, despite an underestimation of daily and hourly highest intensities above 200 mm/day and 40 mm/h, respectively. A comparison of the CP-RCM with its forcing convection-parameterised 12.5 km Regional Climate Model (RCM) demonstrates a clear added value for the CP-RCM, confirming previous studies. Secondly, an object-oriented Lagrangian approach is proposed with the implementation of a precipitating system detection and tracking algorithm, applied to the model and the reference COMEPHORE precipitation dataset for twenty fall seasons. Using French Mediterranean HPEs as objects, CNRM-AROME’s ability to represent the main characteristics of fall convective systems and tracks is highlighted in terms of number, intensity, area, duration, velocity and severity. Further, the model is able to simulate long-lasting and severe extreme fall events similar to observations. However, it fails to reproduce the precipitating systems and tracks with the highest intensities (maximum intensities above 40 mm/h) well, and the model’s tendency to overestimate the cell size increases with intensity.

scholarly journals The Application of Fred Sanders' Teaching to Current Research on Extreme Cold-Season Precipitation Events in the Saint Lawrence River Valley Region

2008 ◽  
Vol 55 ◽  
pp. 241-250 ◽  
Author(s):  
John R. Gyakum
Keyword(s):  
Precipitable Water ◽  
Heavy Precipitation ◽  
Cold Season ◽  
Circulation Anomaly ◽  
Planetary Scale ◽  
Saint Lawrence River ◽  
Physical Insight ◽  
Extreme Cold ◽  
Upper Level ◽  
Precipitation Events

Abstract Fred Sanders' teaching and research contributions in the area of quasigeostrophic theory are highlighted in this paper. The application of these contributions is made to the topic of extreme cold-season precipitation events in the Saint Lawrence valley in the northeastern United States and southern Quebec. This research focuses on analyses of Saint Lawrence valley heavy precipitation events. Synoptic- and planetary-scale circulation anomaly precursors are typically identified several days prior to these events. These precursors include transient upper-level troughs, strong moisture transports into the region, and anomalously large precipitable water amounts. The physical insight of Fred Sanders' work is used in the analysis of these composite results. Further details of this insight are provided in analyses of one case of heavy precipitation.

scholarly journals Will climate change increase the risk of infrastructure failures in Europe due to heavy precipitation?

2016 ◽  
Author(s):  
Katrin M. Nissen ◽  
Uwe Ulbrich
Keyword(s):  
Climate Change ◽  
Regional Climate ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
European Regions ◽  
Event Duration ◽  
Novel Technique ◽  
Climate Simulations ◽  
Daily Events ◽  
Precipitation Events

Abstract. The effect of climate change on potentially infrastructure damaging heavy precipitation events in Europe is investigated in an ensemble of regional climate simulations conducted at a horizontal resolution of 12 km. Based on legislation and stakeholder interviews the 10-year return period is used as a threshold for the detection of relevant events. A novel technique for the identification of heavy precipitation events is introduced. It records not only event frequency but also event size, duration and severity (a measure taking duration, size and rain amount into account) as these parameters determine the potential consequences of the event. Over most of Europe the frequency of relevant heavy precipitation events is predicted to increase with increasing greenhouse gas concentrations. The risk by daily and multi-day events increases at a lower rate than the risk by sub-daily events. The event size is predicted to increase in the future over many European regions, especially for sub-daily events. Moreover, the most severe events were detected in the projection period. The climate change simulations don't show changes in event duration.

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