Influence of Sea Level Pressure on Inter-Annual Rainfall Variability in Northern Senegal in the Context of Climate Change

Abstract This study examines the inter-annual variability of rainfall and mean Sea Level Pressure (SLP) over west Africa based on analysis of the Global Precipitation Climatology Project (GPCP) and National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis respectively. An interconnection is found in this region, between MSLP anomaly (over Azores and St. Helena High) and monthly mean precipitation during summer (June to September: JJAS). We also found that over northern Senegal (15°N-17°N; 17°W-13°W) the SLP to the north is strong; the wind converges at 200hPa corresponding to the position of the tropical Easterly jet (TEJ); the rotational wind 700hPa (corresponding to the position of the AEJ) coming from the north-east is negative. In this region, the precipitation is related to the SLP to the north with the opposite sign. The empirical orthogonal functions (EOF) of SLP are also presented, including the mean spectrum of precipitation and pressures to the north (15°N-40°N and 50°W-25°W) and south (40°S-10°S and 40°W-0°E). The dominant EOF of Sea Level Pressures north and south of the Atlantic Ocean for GPCP represents about 62.2% and 69.4% of the variance, respectively. The second and third EOFs of the pressure to the north account for 24.0% and 6.5% respectively. The second and third EOFs of the pressure to the south represent 12.5% and 8.9% respectively. Wet years in the northern of Senegal were associated with anomalous low-pressure area over north Atlantic Ocean as opposed to the dry years which exhibited an anomalous high-pressure area in the same region. On the other hand, over south Atlantic, an opposition is noted. The wavelet analysis method is applied to the SLP showings to the north, south and precipitation in our study area. The indices prove to be very consistent, especially during intervals of high variance.

Download Full-text

Impacts of Some Climatic Variables on Productivity of Boro rice in South-Western Coastal Regions of Bangladesh

Journal of Environmental Science and Natural Resources ◽

10.3329/jesnr.v9i1.30299 ◽

2016 ◽

Vol 9 (1) ◽

pp. 95-98

Author(s):

MM Islam ◽

MA Farukh ◽

MA Baten

Keyword(s):

Climate Change ◽

Sea Level ◽

Climatic Variability ◽

Rice Production ◽

Maximum Temperature ◽

Climatic Data ◽

Sea Level Pressure ◽

Level Pressure ◽

Average Temperature ◽

Boro Rice

Climate change is the top most important issue in the modern world. Various aspects of Bangladesh are verily affected by climate change. An agro-climatic study was conducted in Khulna, Satkhira and Bagerhat district in Khulna division as well as the Southwestern coastal part of Bangladesh with last 30 (1981-2011) years of some climatic data of average temperature, maximum temperature, seasonal total rainfall, average humidity and sea level pressure to address the climatic variability and its impacts on Boro rice production in Southwestern coastal part of Bangladesh. The average temperature increased by 0.51°C in Boro season in this area. The sea level pressure was about stable here. The Boro rice production increased by 0.04 and 0.3 tha-1 in Khulna and Bagerhat district. However most of the time the production showed increasing trends except in 2007 and 2009 affected by two devastating natural calamities as SIDR and AILA occurred in these two year respectively.J. Environ. Sci. & Natural Resources, 9(1): 95-98 2016

Download Full-text

Interannual to decadal variability within and across the major Eastern Boundary Upwelling Systems

Scientific Reports ◽

10.1038/s41598-019-56514-8 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Giulia Bonino ◽

Emanuele Di Lorenzo ◽

Simona Masina ◽

Doroteaciro Iovino

Keyword(s):

Climate Change ◽

Climate Variability ◽

Sea Level ◽

Low Frequency ◽

Global Ocean ◽

Thermocline Depth ◽

Sea Level Pressure ◽

Level Pressure ◽

Eastern Boundary ◽

Low Frequency Variability

AbstractClimate variability and climate change in Eastern Boundary Upwelling Systems (EBUS) affect global marine ecosystems services. We use passive tracers in a global ocean model hindcast at eddy-permitting resolution to diagnose EBUS low-frequency variability over 1958–2015 period. The results highlight the uniqueness of each EBUS in terms of drivers and climate variability. The wind forcing and the thermocline depth, which are potentially competitive or complementary upwelling drivers under climate change, control EBUS low-frequency variability with different contributions. Moreover, Atlantic and Pacific upwelling systems are independent. In the Pacific, the only coherent variability between California and Humboldt Systems is associated with El Niño Southern Oscillation. The remaining low-frequency variance is partially explained by the North and South Pacific expressions of the Meridional Modes. In the Atlantic, coherent variability between Canary and Benguela Systems is associated with upwelling trends, which are not dynamically linked and represent different processes. In the Canary, a negative upwelling trend is connected to the Atlantic Multi-decadal Oscillation, while in the Benguela, a positive upwelling trend is forced by a global sea level pressure trend, which is consistent with the climate response to anthropogenic forcing. The residual variability is forced by localized offshore high sea level pressure variability.

Download Full-text

Caracterização de Mudanças Climáticas na Antártica a partir da Segunda Metade do Século XX

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v12.6.p2091-2107 ◽

2019 ◽

Vol 12 (6) ◽

pp. 2091

Author(s):

Natália Silva ◽

Ilana Elazari Klein Coaracy Wainer ◽

Marcos Henrique Maruch Tonelli

Keyword(s):

Climate Change ◽

Wind Speed ◽

Sea Level ◽

Southern Hemisphere ◽

Sea Level Pressure ◽

Annular Mode ◽

Level Pressure ◽

British Antarctic Survey ◽

Southern Hemisphere Annular Mode ◽

San Martín

A Antártica é uma região do planeta extremamente sensível às mudanças globais do clima. Para quantificar essas mudanças, é possível estudar a variação de algumas propriedades atmosféricas como temperatura (T), pressão no nível do mar (PNM) e velocidade de ventos (v). Dados de estações meteorológicas espalhadas pela Antártica distribuídos pelo British Antarctic Survey são analisados. Os resultados mostram que as tendências de temperatura apresentam uma distribuição peculiar, visto que na porção oeste do continente há um intenso aquecimento (e.g.,0.55°C/década em San Martin), enquanto que o lado leste observa um resfriamento (-0.06°C/década em Zhongshan). O índice Intervalo de Temperatura Diária (ITD) também é utilizado para caracterizar mudanças climáticas e é consistente com as variações obtidas para a temperatura, caracterizando, portanto, o chamado Padrão de Dipolo na temperatura. Com relação à PNM, 19 estações meteorológicas das 20 estudadas, apresentam tendências negativas e na grande maioria dessas observa-se também intensificação da velocidade dos ventos. Essas mudanças estão associadas principalmente aos modos de variabilidade natural do planeta, sendo que o maior determinante das características climáticas nas regiões extratropicais do Hemisfério Sul é o Modo Anular do Hemisfério Sul (SAM). Characterization of climate change in Antarctica from the second half of 20th CenturyA B S T R A C TAntarctica is a region of the planet extremely sensitive to global climate change. To quantify these changes, it is possible to study the variation of some atmospheric properties such as Temperature, Sea Level Pressure and Wind Speed. Data from meteorological stations in Antarctica provided by the British Antarctic Survey are analyzed. The results show that Temperature trends have a peculiar distribution, since on the western side of the continent there is intense heating (e.g., 0.55°C/decade in San Martin), while the east side observes cooling trends (-0.06°C/decade in Zhongshan). The Daily Temperature Range index is also used to characterize climatic changes and agrees with the variations obtained for the Temperature, thus characterizing the so-called Dipole Pattern in temperature. About the Sea Level Pressure, 19 meteorological stations of the 20 studied, present negative trends and in the great majority of these it is also observed intensification on the wind speed. These changes are mainly associated with the natural modes of variability of the planet, and the Southern Hemisphere Annular Mode (SAM) is the major determinant of the climatic characteristics in the extratropical regions of the Southern Hemisphere.Keywords: Antarctica, Climate Change, Temperature Dipole, Southern Hemisphere Annular Mode.

Download Full-text

The Tropospheric Land–Sea Warming Contrast as the Driver of Tropical Sea Level Pressure Changes

Journal of Climate ◽

10.1175/jcli-d-11-00731.1 ◽

2013 ◽

Vol 26 (4) ◽

pp. 1387-1402 ◽

Cited By ~ 40

Author(s):

Tobias Bayr ◽

Dietmar Dommenget

Keyword(s):

Climate Change ◽

Sea Level ◽

Large Scale ◽

Warm Pool ◽

Sea Level Pressure ◽

Model Simulations ◽

Level Pressure ◽

Pacific Warm Pool ◽

Tropical Sea ◽

Sea Warming

Abstract This article addresses the causes of the large-scale tropical sea level pressure (SLP) changes during climate change. The analysis presented here is based on model simulations, observed trends, and the seasonal cycle. In all three cases the regional changes of tropospheric temperature (Ttropos) and SLP are strongly related to each other [considerably more strongly than (sea) surface temperature and SLP]. This relationship basically follows the Bjerknes circulation theorem, with relatively low regional SLP where there is relatively high Ttropos and vice versa. A simple physical model suggests a tropical SLP response to horizontally inhomogeneous warming in the tropical Ttropos, with a sensitivity coefficient of about −1.7 hPa K−1. This relationship explains a large fraction of observed and predicted changes in the tropical SLP. It is shown that in climate change model simulations the tropospheric land–sea warming contrast is the most significant structure in the regional Ttropos changes relative to the tropical mean changes. Since the land–sea warming contrast exists in the absence of any atmospheric circulation changes, it can be argued that the large-scale response of tropical SLP changes is to first order a response to the tropical land–sea warming contrast. Furthermore, as the land–sea warming contrast is mostly moisture dependent, the models predict a stronger warming and decreasing SLP in the drier regions from South America to Africa and a weaker warming and increasing SLP over the wetter Indo-Pacific warm pool region. This suggests an increase in the potential for deep convection conditions over the Atlantic sector and a decrease over the Indo-Pacific warm pool region in the future.

Download Full-text

High resolution climate projection of storm surge at the Venetian coast

Natural Hazards and Earth System Science ◽

10.5194/nhess-13-1135-2013 ◽

2013 ◽

Vol 13 (4) ◽

pp. 1135-1142 ◽

Cited By ~ 16

Author(s):

R. Mel ◽

A. Sterl ◽

P. Lionello

Keyword(s):

Climate Change ◽

High Resolution ◽

Sea Level ◽

Storm Surge ◽

Climate Model ◽

Surface Wind ◽

Wind Fields ◽

Sea Level Pressure ◽

Weather Forecasts ◽

Level Pressure

Abstract. Climate change impact on storm surge regime is of great importance for the safety and maintenance of Venice. In this study a future storm surge scenario is evaluated using new high resolution sea level pressure and wind data recently produced by EC-Earth, an Earth System Model based on the operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (ECMWF). The study considers an ensemble of six 5 yr long simulations of the rcp45 scenario at 0.25° resolution and compares the 2094–2098 to the 2004–2008 period. EC-Earth sea level pressure and surface wind fields are used as input for a shallow water hydrodynamic model (HYPSE) which computes sea level and barotropic currents in the Adriatic Sea. Results show that a high resolution climate model is needed for producing realistic values of storm surge statistics and confirm previous studies in that they show little sensitivity of storm surge levels to climate change. However, some climate change signals are detected, such as increased persistence of high pressure conditions, an increased frequency of windless hour, and a decreased number of moderate windstorms.

Download Full-text

A multivariate assessment of climate change projections over South America using CMIP5 models

10.5194/egusphere-egu2020-186 ◽

2020 ◽

Author(s):

Paul Loikith ◽

Valerie Thaler ◽

Luana Albertani Pampuch ◽

C. Roberto Mechoso ◽

Armineh Barkhordarian ◽

...

Keyword(s):

Climate Change ◽

South America ◽

Sea Level ◽

Storm Track ◽

Northeastern Brazil ◽

Cmip5 Models ◽

Sea Level Pressure ◽

Level Pressure ◽

Poleward Shift ◽

Model Agreement

<p>A multivariate assessment of climate model projections over South America from the CMIP5 archive is presented. Change in near-surface temperature, precipitation, evapotranspiration, integrated water vapor transport (IVT), sea level pressure, and wind at multiple pressure levels is quantified across the multi-model suite and an assessment of model-to-model agreement on projected change performed. All models project warming by the mid- and late-21<sup>st</sup> century throughout the continent, with the highest magnitude projected over tropical regions. The CMIP5 models are in strong agreement that precipitation will decrease in all seasons over portions of Patagonia, especially along the northern portions of the current-climate mid-latitude storm track. This is consistent with a robustly projected poleward shift of the Pacific extratropical high and mid-latitude storm track indicated by a systematic increase in sea level pressure and decrease in westerly wind over Patagonia. Decreased precipitation for the months of September, October, and November is also projected, with strong model agreement, over portions of northern and northeastern Brazil, coincident with decreases in sea level pressure and increases in evapotranspiration. IVT is broadly projected to decrease over southern South America, coincident with the projected poleward shift of the mid-latitude storm track indicators, with increases projected in the vicinity of the South Atlantic Convergence Zone in austral spring and summer. Further decomposition of the thermodynamic and dynamic components to this change in IVT indicate that the projected decreases in the mid-latitudes are primarily driven by changes in circulation (i.e. dynamic) while the sub-tropical and tropical changes have a predominantly thermodynamic origin. Results provide a comprehensive picture of climate change across South America and highlight where projections should be interpreted with the most confidence.</p>

Download Full-text

Darwin sea level pressure, 1876-1996: Evidence for climate change?

Geophysical Research Letters ◽

10.1029/97gl01789 ◽

1997 ◽

Vol 24 (14) ◽

pp. 1779-1782 ◽

Cited By ~ 39

Author(s):

D. E. Harrison ◽

N. K. Larkin

Keyword(s):

Climate Change ◽

Sea Level ◽

Sea Level Pressure ◽

Level Pressure

Download Full-text

Complex network approach for detecting tropical cyclones

Climate Dynamics ◽

10.1007/s00382-021-05871-0 ◽

2021 ◽

Author(s):

Shraddha Gupta ◽

Niklas Boers ◽

Florian Pappenberger ◽

Jürgen Kurths

Keyword(s):

Sea Level ◽

Tropical Cyclones ◽

Complex Network ◽

Time Scales ◽

Southern Oscillation ◽

Volcanic Eruptions ◽

Network Approach ◽

Sea Level Pressure ◽

Level Pressure ◽

Climate Networks

AbstractTropical cyclones (TCs) are one of the most destructive natural hazards that pose a serious threat to society, particularly to those in the coastal regions. In this work, we study the temporal evolution of the regional weather conditions in relation to the occurrence of TCs using climate networks. Climate networks encode the interactions among climate variables at different locations on the Earth’s surface, and in particular, time-evolving climate networks have been successfully applied to study different climate phenomena at comparably long time scales, such as the El Niño Southern Oscillation, different monsoon systems, or the climatic impacts of volcanic eruptions. Here, we develop and apply a complex network approach suitable for the investigation of the relatively short-lived TCs. We show that our proposed methodology has the potential to identify TCs and their tracks from mean sea level pressure (MSLP) data. We use the ERA5 reanalysis MSLP data to construct successive networks of overlapping, short-length time windows for the regions under consideration, where we focus on the north Indian Ocean and the tropical north Atlantic Ocean. We compare the spatial features of various topological properties of the network, and the spatial scales involved, in the absence and presence of a cyclone. We find that network measures such as degree and clustering exhibit significant signatures of TCs and have striking similarities with their tracks. The study of the network topology over time scales relevant to TCs allows us to obtain crucial insights into the effects of TCs on the spatial connectivity structure of sea-level pressure fields.

Download Full-text

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

Scientific Data ◽

10.1038/s41597-021-00847-5 ◽

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.

Download Full-text