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

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.

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.

scholarly journals Analysis of Atmospheric and Ionospheric Variations Due to Impacts of Super Typhoon Mangkhut (1822) in the Northwest Pacific Ocean

2021 ◽  
Vol 13 (4) ◽  
pp. 661
Author(s):  
Mohamed Freeshah ◽  
Xiaohong Zhang ◽  
Erman Şentürk ◽  
Muhammad Arqim Adil ◽  
B. G. Mousa ◽  
...  
Keyword(s):  
Wind Speed ◽  
Pacific Ocean ◽  
Tropical Cyclone ◽  
Sea Level ◽  
Northwest Pacific ◽  
Northwest Pacific Ocean ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
Super Typhoon ◽  
The Northwest Pacific Ocean

The Northwest Pacific Ocean (NWP) is one of the most vulnerable regions that has been hit by typhoons. In September 2018, Mangkhut was the 22nd Tropical Cyclone (TC) over the NWP regions (so, the event was numbered as 1822). In this paper, we investigated the highest amplitude ionospheric variations, along with the atmospheric anomalies, such as the sea-level pressure, Mangkhut’s cloud system, and the meridional and zonal wind during the typhoon. Regional Ionosphere Maps (RIMs) were created through the Hong Kong Continuously Operating Reference Stations (HKCORS) and International GNSS Service (IGS) data around the area of Mangkhut typhoon. RIMs were utilized to analyze the ionospheric Total Electron Content (TEC) response over the maximum wind speed points (maximum spots) under the meticulous observations of the solar-terrestrial environment and geomagnetic storm indices. Ionospheric vertical TEC (VTEC) time sequences over the maximum spots are detected by three methods: interquartile range method (IQR), enhanced average difference (EAD), and range of ten days (RTD) during the super typhoon Mangkhut. The research findings indicated significant ionospheric variations over the maximum spots during this powerful tropical cyclone within a few hours before the extreme wind speed. Moreover, the ionosphere showed a positive response where the maximum VTEC amplitude variations coincided with the cyclone rainbands or typhoon edges rather than the center of the storm. The sea-level pressure tends to decrease around the typhoon periphery, and the highest ionospheric VTEC amplitude was observed when the low-pressure cell covers the largest area. The possible mechanism of the ionospheric response is based on strong convective cells that create the gravity waves over tropical cyclones. Moreover, the critical change state in the meridional wind happened on the same day of maximum ionospheric variations on the 256th day of the year (DOY 256). This comprehensive analysis suggests that the meridional winds and their resulting waves may contribute in one way or another to upper atmosphere-ionosphere coupling.

scholarly journals Evaluation of a Mesoscale Short-Range Ensemble Forecast System over the Northeast United States

2007 ◽  
Vol 22 (1) ◽  
pp. 36-55 ◽  
Author(s):  
Matthew S. Jones ◽  
Brian A. Colle ◽  
Jeffrey S. Tongue
Keyword(s):  
United States ◽  
Wind Speed ◽  
Sea Level ◽  
Short Range ◽  
Warm Season ◽  
Ensemble Forecast ◽  
Cool Season ◽  
Forecast System ◽  
Sea Level Pressure ◽  
Level Pressure

Abstract A short-range ensemble forecast system was constructed over the northeast United States down to 12-km grid spacing using 18 members from the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). The ensemble consisted of 12 physics members with varying planetary boundary layer schemes and convective parameterizations as well as seven different initial conditions (ICs) [five National Centers for Environmental Prediction (NCEP) Eta-bred members at 2100 UTC and the 0000 UTC NCEP Global Forecast System (GFS) and Eta runs]. The full 18-member ensemble (ALL) was verified at the surface for the warm (May–September 2003) and cool (October 2003–March 2004) seasons. A randomly chosen subset of seven physics (PHS) members at each forecast hour was used to quantitatively compare with the seven IC members. During the warm season, the PHS ensemble predictions for surface temperature and wind speed had more skill than the IC ensemble and a control (shared PHS and IC member) run initialized 12 h later (CTL12). During the cool and warm seasons, a 14-day running-mean bias calibration applied to the ALL ensemble (ALLBC) added 10%–30% more skill for temperature, wind speed, and sea level pressure, with the ALLBC far outperforming the CTL12. For the 24-h precipitation, the PHS ensemble had comparable probabilistic skill to the IC ensemble during the warm season, while the IC subensemble was more skillful during the cool season. All ensemble members had large diurnal surface biases, with ensemble variance approximating ensemble uncertainty only for wind direction. Selection of ICs was also important, because during the cool season the NCEP-bred members introduced large errors into the IC ensemble for sea level pressure, while none of the subensembles (PHS, IC, or ALL) outperformed the GFS–MM5 for sea level pressure.

scholarly journals Daily to intraseasonal oscillations at Antarctic research station Neumayer

2013 ◽  
Vol 26 (2) ◽  
pp. 193-204 ◽  
Author(s):  
N. Rimbu ◽  
G. Lohmann ◽  
G. König-Langlo ◽  
C. Necula ◽  
M. Ionita
Keyword(s):  
Time Series ◽  
Wind Speed ◽  
Sea Level ◽  
Intraseasonal Variability ◽  
Research Station ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
Intraseasonal Oscillations ◽  
Antarctic Research ◽  
And Sea Level

AbstractHigh temporal resolution (three hours) records of temperature, wind speed and sea level pressure recorded at Antarctic research station Neumayer (70°S, 8°W) during 1982–2011 are analysed to identify oscillations from daily to intraseasonal timescales. The diurnal cycle dominates the three-hourly time series of temperature during the Antarctic summer and is almost absent during winter. In contrast, the three-hourly time series of wind speed and sea level pressure show a weak diurnal cycle. The dominant pattern of the intraseasonal variability of these quantities, which captures the out-of-phase variation of temperature and wind speed with sea level pressure, shows enhanced variability at timescales of ∼ 40 days and ∼ 80 days, respectively. Correlation and composite analysis reveal that these oscillations may be related to tropical intraseasonal oscillations via large-scale eastward propagating atmospheric circulation wave-trains. The second pattern of intraseasonal variability, which captures in-phase variations of temperature, wind and sea level pressure, shows enhanced variability at timescales of ∼ 35, ∼ 60 and ∼ 120 days. These oscillations are attributed to the Southern Annular Mode/Antarctic Oscillation (SAM/AAO) which shows enhanced variability at these timescales. We argue that intraseasonal oscillations of tropical climate and SAM/AAO are related to distinct patterns of climate variables measured at Neumayer.

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

2022 ◽  
Vol 12 (01) ◽  
pp. 113-131
Author(s):  
Aichetou Dia-Diop ◽  
Malick Wade ◽  
Sinclaire Zebaze ◽  
Abdoulaye Bouya Diop ◽  
Eric Efon ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Rainfall Variability ◽  
Annual Rainfall ◽  
Sea Level Pressure ◽  
Level Pressure
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