Cloudburst events observed over Uttarakhand during  monsoon season 2017 and their analysis

Cloudburst is an extreme weather event characterised by the occurrence of a large amount of rainfall over a small area within a short span of time with a rainfall of 100 mm or more in one hour. It is responsible for flash flood, inundation of low lying areas and landslides in hills causing extensive damages to life and property. During monsoon season 2017 five number of cloudburst events are observed over Uttarakhand and analysed. Self Recording Rain Gauge (SRRG) and 15 minutes interval data from the newly installed General Packet Radio Service (GPRS) based Automatic Weather Station (AWS) are able to capture the cloudburst events over some areas in Uttarakhand. In this paper, an attempt has been made to find out the significant synoptic and thermodynamic conditions associated with the occurrence of the cloudburst events in Uttarakhand. These 5 cases of cloudburst events that are captured during the month of June, July and August 2017 in Uttarakhand are studied in detail. Synoptically, it is observed that the existence of trough at mean sea level from Punjab to head Bay of Bengal running close to Uttarakhand, the movement of Western Disturbance over north Pakistan and adjoining Jammu & Kashmir and existence of cyclonic circulation over north Rajasthan and neighbourhood are favourable conditions. Also, the presence of strong south-westerly wind flow from the Arabian Sea across West Rajasthan and Haryana on upper air charts are found during these events. Thermodynamically, the Convective Available Potential Energy (CAPE) is found to be high (more than 1100 J/Kg) during most of the cases and vertically integrated precipitable water content (PWC) is more than 55mm. The GPRS based AWS system can help in prediction of the cloud burst event over the specified location with a lead time upto half to one hour in association with radar products.

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Evaluating Forecast Skills of Moisture from Convective-Permitting WRF-ARW Model during 2017 North American Monsoon Season

Atmosphere ◽

10.3390/atmos10110694 ◽

2019 ◽

Vol 10 (11) ◽

pp. 694 ◽

Cited By ~ 1

Author(s):

Christoforus Bayu Risanto ◽

Christopher L. Castro ◽

James M. Moker ◽

Avelino F. Arellano ◽

David K. Adams ◽

...

Keyword(s):

North American ◽

Monsoon Season ◽

Precipitable Water ◽

Weather Forecast ◽

Moisture Flux ◽

Rain Gauge ◽

North American Monsoon ◽

Convective Systems ◽

The North ◽

Northwestern Mexico

This paper examines the ability of the Weather Research and Forecasting model forecast to simulate moisture and precipitation during the North American Monsoon GPS Hydrometeorological Network field campaign that took place in 2017. A convective-permitting model configuration performs daily weather forecast simulations for northwestern Mexico and southwestern United States. Model precipitable water vapor (PWV) exhibits wet biases greater than 0.5 mm at the initial forecast hour, and its diurnal cycle is out of phase with time, compared to observations. As a result, the model initiates and terminates precipitation earlier than the satellite and rain gauge measurements, underestimates the westward propagation of the convective systems, and exhibits relatively low forecast skills on the days where strong synoptic-scale forcing features are absent. Sensitivity analysis shows that model PWV in the domain is sensitive to changes in initial PWV at coastal sites, whereas the model precipitation and moisture flux convergence (QCONV) are sensitive to changes in initial PWV at the mountainous sites. Improving the initial physical states, such as PWV, potentially increases the forecast skills.

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NAM Model Forecasts of Warm-Season Quasi-Stationary Frontal Environments in the Central United States

Weather and Forecasting ◽

10.1175/2010waf2222394.1 ◽

2010 ◽

Vol 25 (4) ◽

pp. 1281-1292 ◽

Cited By ~ 3

Author(s):

Shih-Yu Wang ◽

Adam J. Clark

Keyword(s):

United States ◽

Mesoscale Model ◽

Convective Available Potential Energy ◽

Warm Season ◽

Correlation Coefficients ◽

Precipitable Water ◽

Wind Fields ◽

Vapor Flux ◽

Convective Systems ◽

Central United States

Abstract Using a composite procedure, North American Mesoscale Model (NAM) forecast and observed environments associated with zonally oriented, quasi-stationary surface fronts for 64 cases during July–August 2006–08 were examined for a large region encompassing the central United States. NAM adequately simulated the general synoptic features associated with the frontal environments (e.g., patterns in the low-level wind fields) as well as the positions of the fronts. However, kinematic fields important to frontogenesis such as horizontal deformation and convergence were overpredicted. Surface-based convective available potential energy (CAPE) and precipitable water were also overpredicted, which was likely related to the overprediction of the kinematic fields through convergence of water vapor flux. In addition, a spurious coherence between forecast deformation and precipitation was found using spatial correlation coefficients. Composite precipitation forecasts featured a broad area of rainfall stretched parallel to the composite front, whereas the composite observed precipitation covered a smaller area and had a WNW–ESE orientation relative to the front, consistent with mesoscale convective systems (MCSs) propagating at a slight right angle relative to the thermal gradient. Thus, deficiencies in the NAM precipitation forecasts may at least partially result from the inability to depict MCSs properly. It was observed that errors in the precipitation forecasts appeared to lag those of the kinematic fields, and so it seems likely that deficiencies in the precipitation forecasts are related to the overprediction of the kinematic fields such as deformation. However, no attempts were made to establish whether the overpredicted kinematic fields actually contributed to the errors in the precipitation forecasts or whether the overpredicted kinematic fields were simply an artifact of the precipitation errors. Regardless of the relationship between such errors, recognition of typical warm-season environments associated with these errors should be useful to operational forecasters.

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A 7-Year Climatology of Warm-Sector Heavy Rainfall over South China during the Pre-Summer Months

Atmosphere ◽

10.3390/atmos12070914 ◽

2021 ◽

Vol 12 (7) ◽

pp. 914

Author(s):

Tao Chen ◽

Da-Lin Zhang

Keyword(s):

South China ◽

Heavy Rainfall ◽

Large Scale ◽

Convective Available Potential Energy ◽

Potential Temperature ◽

Vertical Wind Shear ◽

Precipitable Water ◽

Atmospheric Parameter ◽

Low Level ◽

Warm Sector

In view of the limited predictability of heavy rainfall (HR) events and the limited understanding of the physical mechanisms governing the initiation and organization of the associated mesoscale convective systems (MCSs), a composite analysis of 58 HR events over the warm sector (i.e., far ahead of the surface cold front), referred to as WSHR events, over South China during the months of April to June 2008~2014 is performed in terms of precipitation, large-scale circulations, pre-storm environmental conditions, and MCS types. Results show that the large-scale circulations of the WSHR events can be categorized into pre-frontal, southwesterly warm and moist ascending airflow, and low-level vortex types, with higher frequency occurrences of the former two types. Their pre-storm environments are characterized by a deep moist layer with >50 mm column-integrated precipitable water, high convective available potential energy with the equivalent potential temperature of ≥340 K at 850 hPa, weak vertical wind shear below 400 hPa, and a low-level jet near 925 hPa with weak warm advection, based on atmospheric parameter composite. Three classes of the corresponding MCSs, exhibiting peak convective activity in the afternoon and the early morning hours, can be identified as linear-shaped, a leading convective line adjoined with trailing stratiform rainfall, and comma-shaped, respectively. It is found that many linear-shaped MCSs in coastal regions are triggered by local topography, enhanced by sea breezes, whereas the latter two classes of MCSs experience isentropic lifting in the southwesterly warm and moist flows. They all develop in large-scale environments with favorable quasi-geostrophic forcing, albeit weak. Conceptual models are finally developed to facilitate our understanding and prediction of the WSHR events over South China.

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

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-2225-2012 ◽

2012 ◽

Vol 12 (7) ◽

pp. 2225-2240 ◽

Cited By ~ 26

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.

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Extreme runoff response to short-duration convective rainfall in South-West Germany

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-8-10739-2011 ◽

2011 ◽

Vol 8 (6) ◽

pp. 10739-10780

Author(s):

V. Ruiz-Villanueva ◽

M. Borga ◽

D. Zoccatelli ◽

L. Marchi ◽

E. Gaume ◽

...

Keyword(s):

High Resolution ◽

Flash Flood ◽

Rain Gauge ◽

Hydrologic Model ◽

West Germany ◽

Structure Evolution ◽

Model Parameters ◽

Distributed Hydrological Model ◽

Precipitation Frequency ◽

South West

Abstract. The 2 June 2008 flood-producing storm on the Starzel river basin in South-West Germany is examined as a prototype for organized convective systems that dominate the upper tail of the precipitation frequency distribution and are likely responsible for the flash flood peaks in this region. The availability of high-resolution rainfall estimates from radar observations and a rain gauge network, together with indirect peak discharge estimates from a detailed post-event survey, provides the opportunity to study the hydrometeorological and hydrological mechanisms associated with this extreme storm and the ensuing flood. Radar-derived rainfall, streamgauge data and indirect estimates of peak discharges are used along with a distributed hydrologic model to reconstruct hydrographs at multiple locations. The influence of storm structure, evolution and motion on the modeled flood hydrograph is examined by using the "spatial moments of catchment rainfall" (Zoccatelli et al., 2011). It is shown that downbasin storm motion had a noticeable impact on flood peak magnitude. Small runoff ratios (less than 20%) characterized the runoff response. The flood response can be reasonably well reproduced with the distributed hydrological model, using high resolution rainfall observations and model parameters calibrated at a river section which includes most of the area impacted by the storm.

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Optimization of Rain Gauge Networks for Arid Regions Based on Remote Sensing Data

Remote Sensing ◽

10.3390/rs13214243 ◽

2021 ◽

Vol 13 (21) ◽

pp. 4243

Author(s):

Mona Morsy ◽

Ruhollah Taghizadeh-Mehrjardi ◽

Silas Michaelides ◽

Thomas Scholten ◽

Peter Dietrich ◽

...

Keyword(s):

Arid Regions ◽

Flash Flood ◽

Primary Source ◽

Remote Sensing Data ◽

Test Site ◽

Rain Gauge ◽

Cumulative Distribution ◽

Climatic Data ◽

Empirical Cumulative Distribution Function ◽

Rain Gauges

Water depletion is a growing problem in the world’s arid and semi-arid areas, where groundwater is the primary source of fresh water. Accurate climatic data must be obtained to protect municipal water budgets. Unfortunately, the majority of these arid regions have a sparsely distributed number of rain gauges, which reduces the reliability of the spatio-temporal fields generated. The current research proposes a series of measures to address the problem of data scarcity, in particular regarding in-situ measurements of precipitation. Once the issue of improving the network of ground precipitation measurements is settled, this may pave the way for much-needed hydrological research on topics such as the spatiotemporal distribution of precipitation, flash flood prevention, and soil erosion reduction. In this study, a k-means cluster analysis is used to determine new locations for the rain gauge network at the Eastern side of the Gulf of Suez in Sinai. The clustering procedure adopted is based on integrating a digital elevation model obtained from The Shuttle Radar Topography Mission (SRTM 90 × 90 m) and Integrated Multi-Satellite Retrievals for GPM (IMERG) for four rainy events. This procedure enabled the determination of the potential centroids for three different cluster sizes (3, 6, and 9). Subsequently, each number was tested using the Empirical Cumulative Distribution Function (ECDF) in an effort to determine the optimal one. However, all the tested centroids exhibited gaps in covering the whole range of elevations and precipitation of the test site. The nine centroids with the five existing rain gauges were used as a basis to calculate the error kriging. This procedure enabled decreasing the error by increasing the number of the proposed gauges. The resulting points were tested again by ECDF and this confirmed the optimum of thirty-one suggested additional gauges in covering the whole range of elevations and precipitation records at the study site.

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Impact of the Desert dust on the summer monsoon system over Southwestern North America

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-3717-2012 ◽

2012 ◽

Vol 12 (8) ◽

pp. 3717-3731 ◽

Cited By ~ 58

Author(s):

C. Zhao ◽

X. Liu ◽

L. R. Leung

Keyword(s):

North America ◽

Radiative Forcing ◽

Monsoon Season ◽

Lower Atmosphere ◽

Shortwave Radiation ◽

Western Slope ◽

Monsoon Circulation ◽

The North ◽

Moisture Fluxes ◽

June July

Abstract. The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995–2009). During the monsoon season, dust has a cooling effect (−0.90 W m−2) at the surface, a warming effect (0.40 W m−2) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (−0.50 W m−2) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day−1 over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to ~40 % over the eastern slope of the Mountains (Arizona-New~Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the mega-drought conditions projected for the future.

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Ecological status and diversity indices of Panchaule (Dactylorhiza hatagirea) and its associates in Lete village of Mustang district, Nepal

Banko Janakari ◽

10.3126/banko.v26i1.15501 ◽

2016 ◽

Vol 26 (1) ◽

pp. 45-52 ◽

Cited By ~ 1

Author(s):

C. B. Khadka ◽

A. L. Hammet ◽

A. Singh ◽

M. K. Balla ◽

Y. P. Timilsina

Keyword(s):

Monsoon Season ◽

Ecological Status ◽

Diversity Indices ◽

Ecological Value ◽

Conservation Area ◽

Illegal Harvesting ◽

Diverse Community ◽

June July ◽

Important Value Index ◽

Rheum Australe

This paper focuses on the ecological status and diversity indices: Simson’s Index (C), Simson’s Index of Dominance (D) and Shannon-Weaver Index (H) of Dactylorhiza hatagirea and its associates- Rheum australe and Rumex nepalensis in Lete village of Mustang District within the Annapurna Conservation Area. The study was conducted during the monsoon season (June/July) of 2013 in the Lete VDC of Mustang District. The study site possessed an area of 4.5 ha. Altogether, 100 circular plots, each with 25 m2 area, were laid out purposively within the study area; the sampling intensity being 5.55%. The relative frequency, the relative density, the abundance, the relative coverage and the Important Value Index of the species were found to be 61.11, 53.91, 1,061.54, 72.2 and 187.24 respectively. Similarly, the Simson’s Index (C), the Simson’s Index of Dominance (D) and the Shannon-Weaver Index of the species were found to be 0.41, 0.59 and 3.27 respectively, indicating relatively even and relatively diverse community. The study showed relatively higher values of all the parameters of D. hatagirea as compared to its associates indicating good ecological value. However, threats remain due to the illegal harvesting of this valuable orchid and overgrazing in the study site.Banko JanakariA Journal of Forestry Information for NepalVol. 26, No. 1, Page: 45-52, 2016

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How Do Environmental Conditions Influence Vertical Buoyancy Structure and Shallow-to-Deep Convection Transition across Different Climate Regimes?

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-17-0284.1 ◽

2018 ◽

Vol 75 (6) ◽

pp. 1909-1932 ◽

Cited By ~ 6

Author(s):

Yizhou Zhuang ◽

Rong Fu ◽

Hongqing Wang

Keyword(s):

Great Plains ◽

Deep Convection ◽

Convective Available Potential Energy ◽

Central Africa ◽

Research Quality ◽

Free Troposphere ◽

Shallow Convection ◽

Adiabatic Cooling ◽

Thermodynamic Conditions ◽

Atmospheric Radiation Measurement

Abstract We developed an entraining parcel approach that partitions parcel buoyancy into contributions from different processes (e.g., adiabatic cooling, condensation, freezing, and entrainment). Applying this method to research-quality radiosonde profiles provided by the Atmospheric Radiation Measurement (ARM) program at six sites, we evaluated how atmospheric thermodynamic conditions and entrainment influence various physical processes that determine the vertical buoyancy structure across different climate regimes as represented by these sites. The differences of morning buoyancy profiles between the deep convection (DC)/transition cases and shallow convection (SC)/nontransition cases were used to assess preconditions important for shallow-to-deep convection transition. Our results show that for continental sites such as the U.S. Southern Great Plains (SGP) and west-central Africa, surface conditions alone are enough to account for the buoyancy difference between DC and SC cases, although entrainment further enhances the buoyancy difference at SGP. For oceanic sites in the tropical west Pacific, humidity dilution in the lower to middle free troposphere (~1–6 km) and temperature mixing in the middle to upper troposphere (>4 km) have the most important influences on the buoyancy difference between DC and SC cases. For the humid central Amazon region, entrainment in both the boundary layer and the lower free troposphere (~0–4 km) have significant contributions to the buoyancy difference; the upper-tropospheric influence seems unimportant. In addition, the integral of the condensation term, which represents the parcel’s ability to transform available water vapor into heat through condensation, provides a better discrimination between DC and SC cases than the integral of buoyancy or the convective available potential energy (CAPE).

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Topographic amplification of crustal subsidence by the rainwater load of the 2018 heavy rain in SW Japan

10.5194/egusphere-egu21-16260 ◽

2021 ◽

Author(s):

Syachrul Arief

Keyword(s):

Water Vapor ◽

Precipitable Water ◽

Heavy Rain ◽

Satellite System ◽

Rain Gauge ◽

Precipitable Water Vapor ◽

Surface Load ◽

Rain Area ◽

Movement Data ◽

Sw Japan

The huge amount of water vapor in the atmosphere caused disastrous heavy rain and floods in early July 2018 in SW Japan. Here I present a comprehensive space geodetic study of water brought by this heavy rain done by using a dense network of Global Navigation Satellite System (GNSS) receivers.&#160;First, I reconstruct sea level precipitable water vapor above land region on the heavy rain. The total amount of water vapor derived by spatially integrating precipitable water vapor on land was ~25.8 Gt, which corresponds to the bucket size to carry water from ocean to land. I then compiled the precipitation measured with a rain radar network. The data showed the total precipitation by this heavy rain as ~22.11 Gt.Next, I studied the crustal subsidence caused by the rainwater as the surface load. The GNSS stations located under the heavy rain area temporarily subsided 1-2 centimeters and the subsidence mostly recovered in a day. Using such vertical crustal movement data, I estimated the distribution of surface water in SW Japan.&#160;The total amount of the estimated water load on 6 July 2018 was ~68.2 Gt, which significantly exceeds the cumulative on-land rainfalls of the heavy rain day from radar rain gauge analyzed precipitation data. I consider that such an amplification of subsidence originates from the selective deployment of GNSS stations in the concave places, e.g. along valleys and within basins, in the mountainous Japanese Islands.

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