Visual Evidence of Constrained Area of a Cloudburst, 12 June 2018, Tirisha Village, Nubra Valley, Ladakh, India

2020 ◽  
Vol 6 (2) ◽  
pp. 47-57
Author(s):  
Renoj J. Thayyen ◽  
Mritunjay Kumar Singh ◽  
A.P. Dimri

On 12 June 2018, the Tirisha village in Nubra valley, Ladakh experienced a flash flood from a cloudburst that occurred over the mountain ridge. This event was captured in a Sentinel 2B satellite image at the time of its occurrence. The image also provided unique visual evidence of the constrained area of a cloudburst for the first time. Field survey of impact area at the Tirisha village was carried out on 13 June 2018. It was followed by assessment of the impact at the place of occurrence and further downstream using satellite data taken on, before and subsequent days. Satellite data show small area where cloudburst impact (< 1km2) from a cumulonimbus (Cb) cell of ~2.97 km2 of cloud top area. Rest of the flood catchment remained cloud-free during the event and floodwater in the stream is clearly visible in the imagery. The flash flood entered the Tirisha village situated at the Nubra valley foothills, which destroyed a stretch of 100 m road. Previous studies have suggested inherent atmospheric instability over the arid Ladakh region with an extremely high-temperature lapse rate of >9.8 K/km during 40-70 days during summer months. The extremely constrained nature of this event highlights the challenges involved in monitoring, forecasting and managing such events in the Himalayan region.

2021 ◽  
Vol 930 (1) ◽  
pp. 012085
Author(s):  
V Say ◽  
D Legono ◽  
A P Rahardjo ◽  
R A Yuniawan

Abstract Flash flood is a deadly natural disaster that develops at space and time scales caused by high rainfall intensities and frequently occurs. It occurs in mountainous regions with steep slope relief and often causes a loss of economy, society, and environment and threatens human lives. The Ciberang river is located at Lebak district, Banten Province, and has been experiencing a significant flash flood from December 31, 2019 to January 01, 2020, which contributed to various damages, including households nearby the river. In this study, the impact areas were identified with the HEC-RAS model and satellite image data. The impact area was damage on eight sub-districts, including agriculture (77.86 Ha), buildings (0.80 Ha), roads (2.5 km), and nine bridges. In addition, this study tried to build Sabo Dam upstream of Banjar Irigasi sub-districts to respond to the flash flood occurrence. The results have reduced the discharge to around 40 m3/s, and the travel time was delayed about 53 min. The results of this study help the community and decision-makers be ready for further flash flood disasters.


Author(s):  
M. K. Firozjaei ◽  
S. Fathololuomi ◽  
S. K. Alavipanah ◽  
M. Kiavarz ◽  
A. Vaezi ◽  
...  

Abstract. Modeling of Near-Surface Temperature Lapse Rate (NSTLR) is very important in various environmental applications. The Land Surface Temperature (LST) is influenced by many properties and conditions including surface biophysical and topographic characteristics. Some researches have considered the LST - Digital Elevation Model (DEM) feature space to model NSTLR. However, the influence of detailed surface characteristics is rare. This study investigated the impact of surface characteristics on the LST-DEM feature space for NSTLR modeling. A set of remote sensing data including Landsat 8 images, MODIS products, and surface features including DEM and land use of the Balikhli-Chay on 01/07/2018, 18/08/2018 and 03/09/2018 were collected and used in this study. First, Split Window (SW) algorithm was used to estimate LST, and spectral indices were employed to model surface biophysical characteristics. Owing to the impact of surface biophysical and topographic characteristics on the LST-DEM feature space, the NSTLR was calculated for different classes of surface biophysical characteristics, land use, and solar local incident angle. The modeled NSTLR values based on the LST-DEM feature space on 01/07/2018, 18/08/2018 and 03/09/2018 were 8.5, 1.5 and 2.4 °C Km−1; respectively. The NSTLR in different classes of surface biophysical characteristics, land use type and topographical parameters were variable between 0.5 to 14 °C Km−1. This clearly showed the dependence of NSTLR on topographic and biophysical conditions. This provides a new way of calculating surface characteristic specific NSTLR.


2018 ◽  
Vol 18 (14) ◽  
pp. 10799-10823 ◽  
Author(s):  
Aurélien Podglajen ◽  
Riwal Plougonven ◽  
Albert Hertzog ◽  
Eric Jensen

Abstract. Gravity waves are an ubiquitous feature of the atmosphere and influence clouds in multiple ways. Regarding cirrus clouds, many studies have emphasized the impact of wave-induced temperature fluctuations on the nucleation of ice crystals. This paper investigates the impact of the waves on the motion and distribution of ice particles, using the idealized 2-D framework of a monochromatic gravity wave. Contrary to previous studies, special attention is given to the impact of the wind field induced by the wave. Assuming no feedback of the ice on the water vapor content, theoretical and numerical analyses both show the existence of a wave-driven localization of ice crystals, where some ice particles remain confined in a specific phase of the wave. The precise location where the confinement occurs depends on the background relative humidity, but it is always characterized by a relative humidity near saturation and a positive vertical wind anomaly. Hence, the wave has an impact on the mean motion of the crystals and may reduce dehydration in cirrus by slowing down the sedimentation of the ice particles. The results also provide a new insight into the relation between relative humidity and ice crystals' presence. The wave-driven localization is consistent with temperature–cirrus relationships recently observed in the tropical tropopause layer (TTL) over the Pacific during the Airborne Tropical Tropopause EXperiment (ATTREX). It is argued that this effect may explain such observations. Finally, the impact of the described interaction on TTL cirrus dehydration efficiency is quantified using ATTREX observations of clouds and temperature lapse rate.


GeoHazards ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 20-30
Author(s):  
João P. D. Simioni ◽  
Laurindo A. Guasselli ◽  
Gabriel de Oliveira ◽  
Guilherme A. V. Mataveli ◽  
Thiago V. dos Santos

The characterization of water level fluctuations is crucial to explain the hydrological processes that contribute to the maintenance of the structure and function of wetlands. The aim of this study was to develop a method based on remote sensing to characterize and map the water level variation patterns, evapotranspiration, discharge, and rainfall over wetlands in the Gravataí River basin, Rio Grande do Sul (RS), Brazil. For this purpose, ground-based measurements of rainfall, water discharge, and evapotranspiration together with satellite data were used to identify the apparent water level based on the normalized difference water index (NDWI). Our results showed that the variation of the water level followed the rainfall, water discharge, and evapotranspiration seasonal patterns in the region. The NDWI showed similar values to the ground-based data collected 10 days prior to satellite image acquisition. The proposed technique allows for quantifying the pattern of flood pulses, which play an important role for establishing the connectivity between different compartments of wetlands in the study area. We conclude that our methodology based on the use of satellite data and ground measurements was a useful proposition to analyze the water level variation patterns in an area of great importance in terms of environmental degradation and use of agriculture. The information obtained may be used as inputs in hydrologic models, allowing researchers to evaluate the impact, at both local and regional scales, caused by advance of agriculture into natural environments such as wetlands.


2021 ◽  
Author(s):  
Surendra P. Singh ◽  
Ripu Daman Singh ◽  
Surabhi Gumber

Though the highest treelines of the northern hemisphere occur in the Himalaya, the terms treeline and timberline have until very recently been missing from the literature on this region. This book, largely based on research in the Indian Himalaya, attempts to fill the gap on Himalayan treelines. It covers ecology, tree water relations, temperature lapse rate, dendrochronology, tree phenology, distribution patterns, and spatial dimensions of climate warming over the decades. The project, led by the Central Himalayan Environment Association (CHEA) involved 6 research organizations, 11 investigators, and 20 research scholars. Treeline research is providing new and valuable insights into how biota respond to climate change, the relationship between tree-ring growth and climate change in various seasons, the role of growth in relation to stress, seasonal variation in temperature lapse rate and the impact of elevation dependent warming, tree water relations and water conduits in trees, effects of early snow melt, endemism, and future changes.


2017 ◽  
Author(s):  
Aurélien Podglajen ◽  
Riwal Plougonven ◽  
Albert Hertzog ◽  
Eric Jensen

Abstract. Gravity waves are an ubiquitous feature of the atmosphere and influence clouds in multiple ways. Regarding cirrus clouds, many studies have emphasized the impact of wave-induced temperature fluctuations on the nucleation of ice crystals. This paper investigates the impact of the waves on the motion and distribution of ice particles, using the idealized 2-D framework of a monochromatic gravity wave. Contrary to previous studies, a special attention is given to the impact of the wind field induced by the wave. Assuming no feedback of the ice on the water vapor content, theoretical and numerical analyses both show the existence of a wave-driven localization of ice crystals, where some ice particles remain confined in a specific phase of the wave. The precise location where the confinement occurs depends on the background relative humidity, but it is always characterized by a relative humidity near saturation and a positive vertical wind anomaly. Hence, the wave has an impact on the mean motion of the crystals and may reduce dehydration in cirrus by slowing down the sedimentation of the ice particles. The results also provide a new insight into the relation between relative humidity and ice crystals presence. The wave-driven localization is consistent with temperature-cirrus relationships recently observed in the tropical tropopause layer (TTL) over the Pacific during the Airborne Tropical Tropopause EXperiment (ATTREX). It is argued that this effect may explain such observations. Finally, the impact of the described interaction on TTL cirrus dehydration efficiency is quantified using ATTREX observations of clouds and temperature lapse rate.


2013 ◽  
Vol 52 (12) ◽  
pp. 2849-2870 ◽  
Author(s):  
Alexander V. Ryzhkov ◽  
Matthew R. Kumjian ◽  
Scott M. Ganson ◽  
Alexander P. Khain

AbstractSpectral (bin) microphysics models are used to simulate polarimetric radar variables in melting hail. Most computations are performed in a framework of a steady-state, one-dimensional column model. Vertical profiles of radar reflectivity factor Z, differential reflectivity ZDR, specific differential phase KDP, specific attenuation Ah, and specific differential attenuation ADP are modeled at S, C, and X bands for a variety of size distributions of ice particles aloft. The impact of temperature lapse rate, humidity, vertical air velocities, and ice particle density on the vertical profiles of the radar variables is also investigated. Polarimetric radar signatures of melting hail depend on the degree of melting or the height of the radar resolution volume with respect to the freezing level, which determines the relative fractions of partially and completely melted hail (i.e., rain). Simulated vertical profiles of radar variables are very sensitive to radar wavelength and the slope of the size distribution of hail aloft, which is correlated well with maximal hail size. Analysis of relative contributions of different parts of the hail/rain size spectrum to the radar variables allows explanations of a number of experimentally observed features such as large differences in Z of hail at the three radar wavelengths, unusually high values of ZDR at C band, and relative insensitivity of the measurements at C and X bands to the presence of large hail exceeding 2.5 cm in diameter. Modeling results are consistent with S- and C-band polarimetric radar observations and are utilized in Part II for devising practical algorithms for hail detection and determination of hail size as well as attenuation correction and rainfall estimation in the presence of hail.


2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
D. G. Kaskaoutis ◽  
N. Sifakis ◽  
A. Retalis ◽  
H. D. Kambezidis

Satellite data of moderate spatial resolution (MODIS and MERIS) were used to retrieve the aerosol optical depth (AOD) over the urban area of Athens. MODIS products were obtained at a horizontal resolution of 10 by 10 km2centered over Athens, while the differential textural analysis (DTA) code was applied to MERIS images to retrieve relative-to-reference AOD with a resolution of 260 m by 290 m. The possibility of exploiting the full resolution of MERIS data in retrieving AOD over a grid of a few hundreds metres was thereby investigated for the first time. MERIS-based AOD, centred at 560 nm, showed strong positive correlation to ground-basedPM10data (R2= 0.85), while MODIS AOD products were in agreement with both MERIS andPM10. Back trajectories were used to study the impact of atmospheric conditions prevailing during the examined days. Days associated with Saharan air masses corresponded to enhanced AOD and predominance of coarse-mode particles. The results suggest that, at least for the case of Athens, AOD retrieved by MERIS images using the DTA code over cloud-free areas can be related toPM10. The accuracy of retrieval mainly depends on the successful selection of the reference satellite data, namely, an image being least contaminated by tropospheric aerosols.


2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Bibi Tahira ◽  
Naveed Saif ◽  
Muhammad Haroon ◽  
Sadaqat Ali

The current study tries to understand the diverse nature of relationship between personality Big Five Model (PBFM) and student's perception of abusive supervision in higher education institutions of Khyber Pakhtoonkhwa Pakistan. Data was collected in dyads i.e. (supervisors were asked to rate their personality attributes while student were asked to rate the supervisor behavior) through adopted construct. For this purpose, data was collected from three government state universities and one Private Sector University. The focus was on MS/M.Phill and PhD student and their supervisors of the mentioned universities. After measuring normality and validity regression analysis was conducted to assess the impact of supervisor personality characteristics that leads to abusive supervision. Findings indicate interestingly that except agreeableness other four attributes of (PBFM) are play their role for abusive supervision. The results are novel in the nature as for the first time Neuroticism, openness to experience, extraversion and conscientiousness are held responsible for the abusive supervision. The study did not explore the demographic characteristics, and moderating role of organizational culture, justice and interpersonal deviances to understand the strength of relationship in more detail way. Keywords: Personality big five model, abusive supervision, HEIs


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