scholarly journals Long-term trends in the frequency of severe cyclones of Bay of Bengal : Observations and simulations

MAUSAM ◽  
2021 ◽  
Vol 58 (1) ◽  
pp. 59-66
Author(s):  
O. P. SINGH
Keyword(s):  
Tropical Cyclones ◽  
Bay Of Bengal ◽  
Climate Model ◽  
Model Simulation ◽  
Global Climate ◽  
Regional Climate ◽  
North Indian Ocean ◽  
Anthropogenic Activity ◽  
Long Term Trends

The east coast of India and the coasts of Bangladesh, Myanmar and Sri Lanka are vulnerable to the incidence of tropical cyclones of the Bay of Bengal. Every year these cyclones inflict heavy loss of life and property in this region. Global climate change resulting from anthropogenic activity is likely to manifest itself in the weather and climate of the Bay of Bengal region also. The long-term trends in the frequency and intensity of tropical cyclones of the Bay of Bengal during intense cyclonic months May, October and November is one such problem which has been addressed in the present paper.Utilizing the existing data of 129 years (1877-2005) pertaining to the tropical cyclone frequency and intensity in the Bay of Bengal during May, October and November, a study was undertaken to investigate the trends in the frequency of Severe Cyclonic Storms (SCS) during past decades. The results of the trend analysis reveal that the SCS frequency over the Bay of Bengal has registered significant increasing trends in past 129 years during the intense cyclonic months. It may be emphasized that these trends are long-term trends for more than hundred years based on statistical analyses which do not necessarily imply that SCS frequency has increased continuously decade after decade. As a matter of fact there has been a slight decrease in SCS frequency after peaking in the pentad 1966-1970, but this does not alter the long-term trend much. The intensification rate during November, which accounts for highest number of intense cyclones in the north Indian Ocean, has registered a steep rise of 26% per hundred years, implying that a tropical depression forming in the Bay of Bengal during November has a high probability to reach to severe cyclone stage. A regional climate model simulation revealed the enhanced cyclogenesis in the Bay of Bengal during May, October and November as a result of increased anthropogenic emissions in the atmosphere

scholarly journals Internal Variability of the Canadian RCM’s Hydrological Variables at the Basin Scale in Quebec and Labrador

2012 ◽  
Vol 13 (2) ◽  
pp. 443-462 ◽  
Author(s):  
Marco Braun ◽  
Daniel Caya ◽  
Anne Frigon ◽  
Michel Slivitzky
Keyword(s):  
Climate Model ◽  
Model Simulation ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Internal Variability ◽  
Spectral Nudging ◽  
Model Driven ◽  
Basin Scale ◽  
Hydrological Variables

Abstract The effect of a regional climate model’s (RCM’s) internal variability (IV) on climate statistics of annual series of hydrological variables is investigated at the scale of 21 eastern Canada watersheds in Quebec and Labrador. The analysis is carried out on 30-yr pairs of simulations (twins), performed with the Canadian Regional Climate Model (CRCM) for present (reanalysis and global climate model driven) and future (global climate model driven) climates. The twins differ only by the starting date of the regional simulation—a standard procedure used to trigger internal variability in RCMs. Two different domain sizes are considered: one comparable to domains used for RCM simulations over Europe and the other comparable to domains used for North America. Results for the larger North American domain indicate that mean relative differences between twin pairs of 30-yr climates reach ±5% when spectral nudging is used. Larger differences are found for extreme annual events, reaching about ±10% for 10% and 90% quantiles (Q10 and Q90). IV is smaller by about one order of magnitude in the smaller domain. Internal variability is unaffected by the period (past versus future climate) and by the type of driving data (reanalysis versus global climate model simulation) but shows a dependence on watershed size. When spectral nudging is deactivated in the large domain, the relative difference between pairs of 30-yr climate means almost doubles and approaches the magnitude of a global climate model’s internal variability. This IV at the level of the natural climate variability has a profound impact on the interpretation, analysis, and validation of RCM simulations over large domains.

scholarly journals DOWNSCALING TROPICAL CYCLONES FROM GLOBAL RE-ANALYSIS AND SCENARIOS: STATISTICS OF MULTI-DECADAL VARIABILITY OF TC ACTIVITY IN E ASIA

2011 ◽  
Vol 1 (32) ◽  
pp. 17 ◽  
Author(s):  
Hans Von Storch ◽  
Frauke Feser ◽  
Monika Barcikowska
Keyword(s):  
Regional Climate Model ◽  
Tropical Cyclones ◽  
Climate Model ◽  
Decadal Variability ◽  
Tracking System ◽  
Regional Climate ◽  
Automated Tracking ◽  
Stationary Intensity ◽  
Environmental Prediction

An atmospheric regional climate model was employed for describing weather of E Asia for the last decades as well as for the coming century. Re-analyses provided by Global National Center for Environmental Prediction - National Center for Atmospheric Research (NCEP-NCAR) for the past six decades, as well a scenario generated by the ECHAM5/MPI-OM model were dynamically downscaled to a 50 km grid using a state-of-the-art regional climate model (CCLM). Using an automated tracking system, all tropical cyclones (TCs) are identified in the multi-decadal simulations. The different analysis products of TC-statistics were found to differ strongly, also in recent times when the data base was good, so that in the long-term statistics 1950-2010 inhomogeneities mask real climatic variations. The 1948-2009 time series of the annual numbers of TCs in the NCEP-driven simulation and in the JMA best track data (BT) correlate favourably. The number is almost constant, even if there is a slight tendency in BT to show less storms, whereas CCLM shows somewhat more storms, which became more intense. The ECHAM5/MPI-OM-driven scenario simulation, subject to 1959-2100 observed and projected greenhouse gas concentrations, shows a reduction of the number of storms, which maintains a stationary intensity in terms of maximum sustained winds and minimum pressure. Thus, BT-trends and downscaled trends were found to be inconsistent, but also the downscaled trends 1948-2009 and the trends derived from the A1B-scenario were different.

Local effects of global climate change on the urban drainage system of Hamburg

2013 ◽  
Vol 68 (5) ◽  
pp. 1107-1113 ◽  
Author(s):  
Klaus Krieger ◽  
Andreas Kuchenbecker ◽  
Nina Hüffmeyer ◽  
Hans-Reinhard Verworn
Keyword(s):  
Climate Change ◽  
Planning Process ◽  
Climate Model ◽  
Global Climate ◽  
Regional Climate ◽  
Drainage System ◽  
Primary Objective ◽  
Combined Sewer Overflows ◽  
Sewer Network

The Hamburg Water Group owns and operates a sewer network with a total length of more than 5,700 km. There has been increasing attention paid to the possible impacts of predicted changes in precipitation patterns on the sewer network infrastructure. The primary objective of the work presented in this paper is an estimation of the hydraulic impacts of climate change on the Hamburg drainage system. As a first step, simulated rainfalls based on the regional climate model REMO were compared and validated with long-term precipitation measurements. In the second step, the hydraulic effects on the sewer network of Hamburg have been analyzed based on simulated long-term rainfall series for the period of 2000–2100. Simulation results show a significant increase in combined sewer overflows by 50% as well as an increase in surcharges of storm sewer manholes. However, there is still a substantial amount of uncertainty resulting from model uncertainty and unknown development of future greenhouse gas emissions. So far, there seems to be no sound basis for the implementation of an overall climate factor for sewer dimensioning for the Hamburg region. Nevertheless, possible effects of climate change should be taken into account within the planning process for major sewer extensions or modifications.

scholarly journals A Northern Hemisphere Volcanic Chemistry Record (1869–1984) and Climatic Implications Using a South Greenland Ice Core

1990 ◽  
Vol 14 ◽  
pp. 176-182 ◽  
Author(s):  
W.B. Lyons ◽  
P.A. Mayewski ◽  
M.J. Spencer ◽  
M.S. Twickler ◽  
T.E. Graedel
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Chemical Signatures ◽  
Time Period ◽  
Tree Ring Data ◽  
Long Term Trends ◽  
Major Chemical

The effect of volcanic emission of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869–1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60–90 °N. Many authors have pointed out that the amount of volcanic acids such as HCl and H2SO4 injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ∼1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism-climatic linkage.

scholarly journals Regional climate changes due to double CO2 simulation by CCM3

MAUSAM ◽  
2021 ◽  
Vol 52 (1) ◽  
pp. 221-228
Author(s):  
P. K. PAL ◽  
P. K. THAPLIYAL ◽  
A. K. DWAVEDI
Keyword(s):  
Climate Changes ◽  
Climate Model ◽  
Regional Climate ◽  
Longwave Radiation ◽  
Model Atmosphere ◽  
Total Rainfall ◽  
Long Term Trends ◽  
Temporal And Spatial ◽  
Equilibrium Experiment

An equilibrium experiment has been conducted with CCM3 climate model in which the amount of CO2 in  the model atmosphere is doubled and the differences in resulting climate has been examined. The results show that there is an overall decrease in outgoing longwave radiation indicating the possible increase in cloudiness. The total rainfall may not change significantly but the temporal and spatial distributions over India are likely to change as observed in past long term trends.

scholarly journals Sensitivity study of the REMO regional climate model to domain size

2021 ◽  
Vol 18 ◽  
pp. 157-167
Author(s):  
Réka Suga ◽  
Otília A. Megyeri-Korotaj ◽  
Gabriella Allaga-Zsebeházi
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Domain Size ◽  
Sensitivity Study ◽  
Horizontal Resolution ◽  
Precipitation Indices

Abstract. In the framework of the KlimAdat national project, the Hungarian Meteorological Service (OMSZ) is aiming to perform 10 km horizontal resolution simulations with the 2015 version of the REMO regional climate model over Central and Eastern Europe. The long-term simulations were preceded by a 10-year long sensitivity study on domain size, which is summarised in this paper. We selected three different domains embedded in each other, which contain the whole area of the Danube and Tisza river catchments. Lateral boundary conditions were obtained from the 50 km resolution REMO driven by the MPI-ESM-LR global climate model. Simulations were performed for the period of 1970–1980 including 1-year spin-up. Monthly and seasonal means of daily 2 m temperature, precipitation sum and several precipitation indices were evaluated. Reference datasets were E-OBS 19.0 and CarpatClim-HU. We can conclude, that the selection of domain size has a larger impact on the simulation of precipitation, and in the case of the seasonal mean of the precipitation indices, the differences amongst the results obtained on each model domain exceed 10 %. In general, the smallest biases occurred on the largest domain, therefore further long-term simulations are being produced on this domain.

scholarly journals A Northern Hemisphere Volcanic Chemistry Record (1869–1984) and Climatic Implications Using a South Greenland Ice Core

1990 ◽  
Vol 14 ◽  
pp. 176-182 ◽  
Author(s):  
W.B. Lyons ◽  
P.A. Mayewski ◽  
M.J. Spencer ◽  
M.S. Twickler ◽  
T.E. Graedel
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Chemical Signatures ◽  
Time Period ◽  
Tree Ring Data ◽  
Long Term Trends ◽  
Major Chemical

The effect of volcanic emission of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869–1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60–90 °N. Many authors have pointed out that the amount of volcanic acids such as HCl and H2SO4injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ∼1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism-climatic linkage.

scholarly journals A new bias-correction method for precipitation over complex terrain suitable for different climate states: a case study using WRF (version 3.8.1)

2020 ◽  
Vol 13 (10) ◽  
pp. 5007-5027
Author(s):  
Patricio Velasquez ◽  
Martina Messmer ◽  
Christoph C. Raible
Keyword(s):  
Regional Climate Model ◽  
Bias Correction ◽  
Complex Terrain ◽  
Climate Model ◽  
Model Simulation ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Correction Method ◽  
Bias Correction Method

Abstract. This work presents a new bias-correction method for precipitation over complex terrain that explicitly considers orographic characteristics. This consideration offers a good alternative to the standard empirical quantile mapping (EQM) method during colder climate states in which the orography strongly deviates from the present-day state, e.g. during glacial conditions such as the Last Glacial Maximum (LGM). Such a method is needed in the event that absolute precipitation fields are used, e.g. as input for glacier modelling or to assess potential human occupation and according migration routes in past climate states. The new bias correction and its performance are presented for Switzerland using regional climate model simulations at 2 km resolution driven by global climate model outputs obtained under perpetual 1990 and LGM conditions. Comparing the present-day regional climate model simulation with observations, we find a strong seasonality and, especially during colder months, a height dependence of the bias in precipitation. Thus, we suggest a three-step correction method consisting of (i) a separation into different orographic characteristics, (ii) correction of very low intensity precipitation, and (iii) the application of an EQM, which is applied to each month separately. We find that separating the orography into 400 m height intervals provides the overall most reasonable correction of the biases in precipitation. The new method is able to fully correct the seasonal precipitation bias induced by the global climate model. At the same time, some regional biases remain, in particular positive biases over high elevated areas in winter and negative biases in deep valleys and Ticino in winter and summer. A rigorous temporal and spatial cross-validation with independent data exhibits robust results. The new bias-correction method certainly leaves some drawbacks under present-day conditions. However, the application to the LGM demonstrates that it is a more appropriate correction compared to the standard EQM under highly different climate conditions as the latter imprints present-day orographic features into the LGM climate.

scholarly journals Simulations of frequency, intensity and tracks of cyclonic disturbances in the Bay of Bengal and the Arabian Sea

MAUSAM ◽  
2021 ◽  
Vol 60 (2) ◽  
pp. 167-174
Author(s):  
O. P. SINGH
Keyword(s):  
Greenhouse Gas ◽  
Bay Of Bengal ◽  
Andhra Pradesh ◽  
Arabian Sea ◽  
Climate Model ◽  
Global Climate ◽  
North Indian Ocean ◽  
Post Monsoon ◽  
Cyclonic Disturbances ◽  
Monsoon Depressions

The paper presents the results of simulation experiments conducted for the assessment of likely changes in the cyclogenesis pattern in the Bay of Bengal (BOB) and the Arabian Sea (AS) resulting from global climate change. Two experiments were performed, namely the ‘control’ (CTL) experiment in which the greenhouse gas concentration in the atmosphere was fixed as per 1990 levels and the ‘greenhouse gas’ (GHG) experiment in which an annual compound increase of 1% from 1990 onwards was introduced. CTL and GHG experiments of 20 years length were performed for the period 2041-2060. The model used is the regional climate model Had RM2 of the Hadley Centre of Climate Prediction and Research, U.K.    The results have brought out some significant changes in the cyclogenesis pattern in the North Indian Ocean (BOB and AS). The most significant likely change is the increase in the frequency of post-monsoon storms in the Bay of Bengal. The experiments show an increase of about 50% in the post-monsoonal cyclogenesis by 2041-2060 as a result of increased greenhouse gas concentrations in the atmosphere. The frequency of monsoon depressions / storms in the BOB is likely to decrease considerably during June-August. Due to varying impacts in different seasons, the annual frequency of cyclonic disturbances may change marginally in the BOB. In the Arabian Sea, however the model has simulated a significant reduction in the frequency which may be halved by the period 2041-2060. The results show intensification of storms during May-June and September-November. The monsoon depressions  during July-August are  likely to become less intense.   In GHG experiment most of the post-monsoon storms have a tendency to strike north Andhra-Orissa coasts whereas in CTL experiment the storms strike coast from Tamilnadu to south Orissa. Thus, the focus of post-monsoon storms in the BOB is likely to shift northwards from Tamilnadu-Andhra Pradesh coast to north Andhra Pradesh-south Orissa coast. Another important simulated change in storm tracks is that more number of pre-monsoon storms in the BOB may have a tendency to recurve north or northeastwards by 2041-2060.

scholarly journals Response of Summer Precipitation over Eastern China to Large Volcanic Eruptions

2010 ◽  
Vol 23 (3) ◽  
pp. 818-824 ◽  
Author(s):  
Youbing Peng ◽  
Caiming Shen ◽  
Wei-Chyung Wang ◽  
Ying Xu
Keyword(s):  
Climate Model ◽  
Model Simulation ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Eastern China ◽  
Summer Precipitation ◽  
Volcanic Eruptions ◽  
Global Climate Model Simulation ◽  
Large Volcanic Eruptions

Abstract Studies of the effects of large volcanic eruptions on regional climate so far have focused mostly on temperature responses. Previous studies using proxy data suggested that coherent droughts over eastern China are associated with explosive low-latitude volcanic eruptions. Here, the authors present an investigation of the responses of summer precipitation over eastern China to large volcanic eruptions through analyzing a 1000-yr global climate model simulation driven by natural and anthropogenic forcing. Superposed epoch analyses of 18 cases of large volcanic eruption indicate that summer precipitation over eastern China significantly decreases in the eruption year and the year after. Model simulation suggests that this reduction of summer precipitation over eastern China can be attributed to a weakening of summer monsoon and a decrease of moisture vapor over tropical oceans caused by large volcanic eruptions.

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