scholarly journals Value addition in district level dynamical forecast during monsoon depressions and storms

MAUSAM ◽  
2021 ◽  
Vol 58 (1) ◽  
pp. 1-8
Author(s):  
O. P. SINGH ◽  
B. LAL ◽  
ONKARI PRASAD
Keyword(s):  
Sea Level ◽  
Heavy Rainfall ◽  
Rainfall Amount ◽  
District Level ◽  
Value Addition ◽  
Maximum Rainfall ◽  
Mean Sea Level ◽  
Weather Forecasts ◽  
Medium Range ◽  
Monsoon Depressions

ABSTRACT. The trials of district level forecasts yielded encouraging results during 2005 monsoon. The purpose of this paper is to document the methodology followed in the value addition during the periods of monsoon depressions and storms. The focus is on the use of Mean Sea Level (MSL) positions and the 850 hPa circulation features predicted by different model centres, especially the European Centre for Medium-Range Weather Forecasts (ECMWF). The ECMWF-predicted 72 hr MSL position of the monsoon depression centre was found to be significantly correlated to the actual position of the system and the central location of the realized rainfall zone associated with the system. Even the predicted location of the system at 850 hPa by the ECMWF has been found useful in identifying the districts that received heaviest rainfall associated with the monsoon systems.MM5 and T-80 – predicted locations of the system at 850 hPa yielded lower correlations with the location of the actual rainfall zone associated with the system. As ECMWF – predicted rainfall was not available the rainfall predicted by MM5 and T-80 were used in the computations of the correlations with actual rainfall amounts associated with monsoon depressions and storms. The correlations between MM5 and T-80 – predicted average and maximum rainfall associated with systems and corresponding actual were poor. Though it is not difficult to identify the districts that are likely to be affected by the heavy rainfall associated with monsoon depressions/storms, the prediction of exact rainfall amount for each district (beyond heavy, very heavy or exceptionally heavy categories) is difficult from the model outputs which makes such forecasts a very challenging task. Therefore, the value addition using other inputs such as satellite information, synoptic charts, climatology etc. are very useful in the prediction of rainfall amounts associated with monsoon systems.

scholarly journals Tropical cyclone simulations over Bangladesh at convection permitting 4.4 km & 1.5 km resolution

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Sea Level ◽  
Tropical Cyclones ◽  
Weather Forecasting ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Level Pressure ◽  
Medium Range ◽  
Gust Speed

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.

Some Aspects of the Ecology of Lake Macquarie, N.S.W., with Regard to an Alleged Depletion of Fish. II. Hydrology

1959 ◽  
Vol 10 (3) ◽  
pp. 279 ◽  
Author(s):  
RS Spencer
Keyword(s):  
Sea Level ◽  
Fresh Water ◽  
Oxygen Tension ◽  
Heavy Rainfall ◽  
Salt Water ◽  
Water Discharge ◽  
Narrow Channel ◽  
Mean Sea Level ◽  
Lake Temperature ◽  
Fresh Water Discharge

Lake Macquarie is a marine-dominated drowned valley connected to the sea by a shallow narrow channel which damps tidal oscillations from 5 ft on the coast outside to about 3 in. in the like. Superimposed on the semi-diurnal tides are changes in level in response to changes both in the external daily mean sea-level and in the volume of fresh water discharge into the lake. Temperature and chlorinity cycles are closely linked. Discharge from the creeks supplies phosphate but little nitrate for the lake. Prolonged heavy rainfall in both 1955 and 1956 produced stratification of the water associated with lowered oxygen tension in the underlying salt water. There is evidence of a wind-generated circulation within the lake.

scholarly journals A new framework for probabilistic seasonal forecasts based on circulation type classifications and driven by an ensemble global model

2018 ◽  
Vol 15 ◽  
pp. 183-190 ◽  
Author(s):  
Gianni Messeri ◽  
Riccardo Benedetti ◽  
Alfonso Crisci ◽  
Bernardo Gozzini ◽  
Matteo Rossi ◽  
...  
Keyword(s):  
Sea Level ◽  
Geopotential Height ◽  
Circulation Type ◽  
Seasonal Forecasts ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Circulation Types ◽  
Temperature And Precipitation ◽  
Medium Range ◽  
New Framework

Abstract. In the last years coupled atmospheric ocean climate models have remarkably improved medium range seasonal forecasts, especially on middle latitude areas such as Europe and the Mediterranean basin. In this study a new framework for medium range seasonal forecasts is proposed. It is based on circulation types extracted from long range global ensemble models and it aims at two goals: (i) an easier use of the information contained in the complex system of atmospheric circulations, through their reduction to a limited number of circulation types and (ii) the computation of high spatial resolution probabilistic forecasts for temperature and precipitation. The proposed framework could be also useful to lead predictions of weather-derived parameters, such as the risk of heavy rainfall, drought or heat waves, with important impacts on agriculture, water management and severe weather risk assessment. Operatively, starting from the ensemble predictions of mean sea level pressure and geopotential height at 500 hPa of the NCEP – CFSv2 long range forecasts, the third-quantiles probabilistic maps of 2 m temperature and precipitation are computed through a Bayesian approach by using E-OBS 0.25∘ gridded datasets. Two different classification schemes with nine classes were used: (i) Principal Component Transversal (PCT9), computed on mean sea level pressure and (ii) Simulated Annealing Clustering (SAN9), computed on geopotential height at 500 hPa. Both were chosen for their best fit concerning the ground-level precipitation and temperature stratification for the Italian peninsula. Following this approach an operative chain based on a very flexible and exportable method was implemented, applicable wherever spatially and temporally consistent datasets of weather observations are available. In this paper the model operative chain, some output examples and a first attempt of qualitative verification are shown. In particular three case studies (June 2003, February 2012 and July 2014) were examined, assuming that the ensemble seasonal model correctly predicts the circulation type occurrences. At least on this base, the framework here proposed has shown promising performance.

scholarly journals The Winter Rainfall of Malaysia

2013 ◽  
Vol 26 (3) ◽  
pp. 936-958 ◽  
Author(s):  
Tsing-Chang Chen ◽  
Jenq-Dar Tsay ◽  
Ming-Cheng Yen ◽  
Jun Matsumoto
Keyword(s):  
South China Sea ◽  
Heavy Rainfall ◽  
Peninsular Malaysia ◽  
Rainfall Amount ◽  
Severe Weather ◽  
Winter Rainfall ◽  
Maximum Rainfall ◽  
Cold Surge ◽  
Dynamic Analyses ◽  
Rainfall Flood

Abstract Malaysia is geographically separated into Peninsular Malaysia and west Borneo. The rainfall maximum in the former region occurs during November–December, whereas that in the latter region occurs during December–February. This difference of maximum rainfall period indicates that the formation mechanism is different for the rainfall centers in these two parts of Malaysia. Since rainfall is primarily produced by severe weather systems, the formation of a climatological rainfall center is explored through synoptic activity and the rainfall amount of this center is estimated through contributions by rain-producing disturbances. The major cause of the rainfall maximum of Peninsular Malaysia is cold surge vortices (CSVs) and heavy rainfall/flood (HRF) events propagating from the Philippine area and Borneo. In contrast, the major cause of the rainfall maximum of Borneo is these rain-producing disturbances trapped in Borneo. Disturbances of the former group are formed by the cold surge flows of the Philippine Sea type, whereas disturbances of the latter group are formed by cold surge flows of the South China Sea (SCS) type. The population of HRF events is about one-fourth of the rain-producing disturbances in both Peninsular Malaysia and Borneo, but they produce less than ~60% rainfall for these two regions. It is revealed from the synoptic and dynamic analyses that the major Borneo rain-producing disturbances propagate westward before December by strong tropical easterlies, but they are trapped after December by strong northeasterlies of the SCS-type cold surge flow.

scholarly journals District level value-added dynamical-synoptic forecast system for rainfall

MAUSAM ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 209-220
Author(s):  
B. LAL ◽  
O. P. SINGH ◽  
ONKARI PRASAD ◽  
S. K. ROY BHOWMIK ◽  
S. R. KALSI ◽  
...  
Keyword(s):  
Weather Forecasting ◽  
Value Added ◽  
India Meteorological Department ◽  
Southwest Monsoon ◽  
District Level ◽  
New Delhi ◽  
Weather Forecasts ◽  
Synoptic Weather ◽  
Mm5 Model ◽  
Medium Range

Lkkj & bl ’kks/k&Ik= esa o"kkZ ls lacaf/kr ftyk Lrjh; ekuksa ij vk/kkfjr xfrdh; flukfIVd iwokZuqeku dh Ik)fr vkSj mlds iz;ksxkRed ifj.kkeksa dks izLrqr fd;k x;k gSA blds igys bl rduhd dk mi;ksx o"kZ 2005 dh ekulwu iwoZ dh _rq] nf{k.kh if’peh ekulwu _rq vkSj ekulwu ds Ik’pkr dh _rq ds nkSjku gqbZ ftysokj o"kkZ dk iwokZuqeku yxkus ds fy, fd;k x;k FkkA mDr 2005 ds iwokZuqeku ds fy, Vh-&80],e- ,e- 5] jk"Vªh; e/; vof/k ekSle iwokZuqeku dsUnz ¼,u- lh- ,e- vkj- MCY;w- ,Q-½ ds- bZ- Vh- ,- vkSj Hkkjr ekSle foKku foHkkx esa dk;Z’khy ,e- ,e- 5 xfrdh; fun’kksZa dk lefUor #Ik ls mi;ksx fd;k x;k FkkA iwokZuqeku esa lefUor #Ik ls ;ksxnku nsus okys lHkh fun’kksZa ds ekuksa dk vyx&vyx ewY;kadu djds muls izkIr gq, o"kkZ ds iwokZuqekuksa dk mi;ksx djds xfrdh; iwokZuqeku rS;kj fd;k x;k gSA ifjpkyu y{k.kksa] m/okZ/kj osx] mixzg ls izkIr lwpuk flukfIVd pkVksZa vkSj tyok;q foKku vkfn tSls vU; fun’kksZa dk vkdyu djds xfrdh; iwokZuqekuksa dks eku vk/kkfjr ¼osY;w ,fMM ½ flukfIVd ekSle iwokZuqekuksa esa ifjofrZr fd;k x;k gSA o"kZ 2005 esa fd, x, iwokZuqeku ds vuqHko ls ;g irk pyk gS fd lefUor #Ik ls ;ksxnku nsus okys fun’kksZa ls vyx&vyx izkIr gq, o"kkZ ds iwokZuqekuksa dh fuiq.krk dh rqyuk esa eku&vk/kkfjr ¼osY;w ,fMM ½ xfrdh; flukfIVd iz.kkyh ds 24, 48, 72 ?kaVksa ds ftyk Lrjh; o"kkZ ds iwokZuqeku dgha vf/kd fuiq.krk ls rS;kj fd, tk ldrs gSaA The paper presents the methodology and trial results of the district level value-added dynamical-synoptic forecast for rainfall. The technique was tried for forecasting districtwise rainfall during Pre-monsoon, Southwest Monsoon and Post monsoon seasons of 2005. The constituent dynamical models were T-80, MM5, ETA of the National Centre for Medium Range Weather Forecasting (NCMRWF) and the MM5 model operational at India Meteorological Department, New Delhi. The dynamical predictions were prepared using the rainfall predictions of the constituent models by assigning different weights. The dynamical predictions were converted into value-added synoptic-weather forecasts by taking into account other inputs like circulation features, vertical velocity, satellite information, synoptic charts and climatology etc. The experience during 2005 has shown that the value-added dynamical-synoptic system can produce 24, 48, 72 hours district level rainfall forecast of greater skill than the skills of the constituent models.

scholarly journals Value addition in district level dynamical forecast during intense rainfall spells over the west coast of India

MAUSAM ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 411-418
Author(s):  
B. LAL ◽  
O. P. SINGH ◽  
ONKARI PRASAD
Keyword(s):  
West Coast ◽  
Arabian Sea ◽  
Heavy Rainfall ◽  
Weather Forecasting ◽  
District Level ◽  
Intense Rainfall ◽  
Value Addition ◽  
The West ◽  
Maximum Wind ◽  
West Coast Of India

lkj & ekulwu _rq ds nkSjku Hkkjr ds if’peh rV ij Hkkjh o"kkZ dh ?kVukvksa dk vjc lkxj ds Åij iouksa dh vf/kdre xfr ds ØksM ¼dksj½ ds lkFk ?kfu"B laca/k gSA bl 'kks/k&i= esa bZ- lh- ,e- MCY;w- ,Q- ¼;wjksih; e/;e vof/k iwokZuqeku dsUnz½ }kjk 850 gSDVkikLdy ij iwokZuqekfur 72 ?kaVs ds izokg izfr:i  dk mi;ksx fd;k x;k gS ftlls if’peh rV ij Hkkjh o"kkZ dk iwokZuqeku djus ds fy, ftyk Lrjh; xfrdh; iwokZuqeku iz.kkyh dh {kerk c<+kus gsrq ek=kRed i)fr dk fodkl fd;k tk ldsA ;g ns[kk x;k gS fd if’peh rV ij o"kkZ dh ek=k dk if’peh rV ij vjc lkxj esa iou dh vf/kdre xfr ds 72 ?kaVs ds bZ- lh- ,e- MCY;w- ,Q- }kjk fd, x, iwokZuqeku ds lkFk egRoiq.kZ lglaca/k gSA if’peh rV ij Hkkjh o"kkZ ds {ks= ds v{kka’kh; foLrkj dk if’peh rV ij iou dh vf/kdre xfr ds ØksM ¼dksj½ ds lkFk egRoiw.kZ lglaca/k gSA bl 'kks/k&i= esa  ;g crk;k x;k gS fd xzh"edkyhu ekulwu _rq ds nkSjku Hkkjr ds if’peh rV ij Hkkjh o"kkZ ds 72 ?kaVs dk iwokZuqeku djus ds fy, iouksa dh vf/kdre xfr ds 72 ?kaVs ds iwokZuqekfur ØksM ¼dksj½ vkSj foLrkj dh rhozrk vkSj fLFkfr dh {kerk c<+kus ds fy, laHkkfor iwoZlwpdksa ds :i esa mi;ksx fd;k tk ldrk gSA Occurrences of intense rainfall events over west coast of India during monsoon are intimately linked to the core of maximum winds over the Arabian Sea. ECMWF (Europian Centre for Medium Range Weather Forecasting )  predicted 72 hr flow pattern at 850 hPa has been used to develop a quantitative method for value addition in the district level dynamical forecast system for intense rainfall over the west coast. It has been found that the amount of rainfall over the west coast is significantly correlated to 72 hr ECMWF forecast of maximum wind speed over the Arabian Sea along the west coast. The latitudinal width of the heavy rainfall belt over the west coast has got significant correlation with the location of maximum wind core along the west coast. It has been  shown that the strength and location of the 72 hr predicted core and fetch of maximum winds could be used as potential predictors in the value addition for 72 hr heavy rainfall forecast along the west coast of India during summer monsoon.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

scholarly journals Deterministic approach for multiple-source tsunami hazard assessment for Sines, Portugal

2015 ◽  
Vol 15 (11) ◽  
pp. 2557-2568 ◽  
Author(s):  
M. Wronna ◽  
R. Omira ◽  
M. A. Baptista
Keyword(s):  
Sea Level ◽  
Wave Height ◽  
Hazard Assessment ◽  
Test Site ◽  
Tsunami Hazard ◽  
Deterministic Approach ◽  
Flow Depth ◽  
Mean Sea Level ◽  
Tsunami Hazard Assessment ◽  
The Impact

Abstract. In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and container terminals. The port and its industrial infrastructures face the ocean southwest towards the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING, a Non-linear Shallow Water model wIth Nested Grids. In this study, the static effect of tides is analysed for three different tidal stages: MLLW (mean lower low water), MSL (mean sea level), and MHHW (mean higher high water). For each scenario, the tsunami hazard is described by maximum values of wave height, flow depth, drawback, maximum inundation area and run-up. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at the Sines test site considering the single scenarios at mean sea level, the aggregate scenario, and the influence of the tide on the aggregate scenario. The results confirm the composite source of Horseshoe and Marques de Pombal faults as the worst-case scenario, with wave heights of over 10 m, which reach the coast approximately 22 min after the rupture. It dominates the aggregate scenario by about 60 % of the impact area at the test site, considering maximum wave height and maximum flow depth. The HSMPF scenario inundates a total area of 3.5 km2.

scholarly journals Flooding Conditions at Aveiro Port (Portugal) within the Framework of Projected Climate Change

2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Américo Soares Ribeiro ◽  
Carina Lurdes Lopes ◽  
Magda Catarina Sousa ◽  
Moncho Gomez-Gesteira ◽  
João Miguel Dias
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Climate Change Impacts ◽  
Storm Surges ◽  
Historical Period ◽  
Return Periods ◽  
Wave Regime ◽  
Mean Sea Level ◽  
Sea Levels ◽  
Far Future

Ports constitute a significant influence in the economic activity in coastal areas through operations and infrastructures to facilitate land and maritime transport of cargo. Ports are located in a multi-dimensional environment facing ocean and river hazards. Higher warming scenarios indicate Europe’s ports will be exposed to higher risk due to the increase in extreme sea levels (ESL), a combination of the mean sea level, tide, and storm surge. Located on the west Iberia Peninsula, the Aveiro Port is located in a coastal lagoon exposed to ocean and river flows, contributing to higher flood risk. This study aims to assess the flood extent for Aveiro Port for historical (1979–2005), near future (2026–2045), and far future (2081–2099) periods scenarios considering different return periods (10, 25, and 100-year) for the flood drivers, through numerical simulations of the ESL, wave regime, and riverine flows simultaneously. Spatial maps considering the flood extent and calculated area show that most of the port infrastructures' resilience to flooding is found under the historical period, with some marginal floods. Under climate change impacts, the port flood extent gradually increases for higher return periods, where most of the terminals are at high risk of being flooded for the far-future period, whose contribution is primarily due to mean sea-level rise and storm surges.

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