Recent climate changes in precipitable water in the global tropics as revealed in National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis

2003 ◽  
Vol 108 (D10) ◽  
Author(s):  
Igor I. Zveryaev
Keyword(s):  
Climate Changes ◽  
Precipitable Water ◽  
Atmospheric Research ◽  
Recent Climate ◽  
Environmental Prediction

scholarly journals Método objetivo de identificação dos vórtices ciclônicos de altos níveis na região Tropical Sul: validação

2010 ◽  
Vol 25 (3) ◽  
pp. 311-323 ◽  
Author(s):  
Michelyne Duarte Leal Coutinho ◽  
Manoel Alonso Gan ◽  
Vadlamudi Brahmananda Rao
Keyword(s):  
Atmospheric Research ◽  
Environmental Prediction

Neste estudo foi desenvolvido um Método Objetivo (MO) para identificar Vórtices Ciclônicos de Altos Níveis (VCANs) na região Tropical Sul, baseado na vorticidade relativa e no escoamento horizontal do vento ao redor do centro dos sistemas. O MO foi elaborado usando dados de reanálises do National Centers for Environmental Prediction - National Centers for Atmospheric Research (NCEP-NCAR) e validado, para o período de cinco anos (2002 a 2006), através da comparação entre os resultados obtidos pelo MO e os obtidos pela Análise dos Campos (AC) de vento e vorticidade relativa. Por outro lado, uma avaliação da AC em identificar os VCANs foi feita, para o mesmo período, através da comparação entre os resultados desta e os obtidos usando Imagem de Satélite (IS) no canal espectral do vapor d'água. As AC apresentaram resultados satisfatórios e, portanto, o conjunto dos dados de reanálises do NCEP-NCAR foi aplicado ao MO. Foi observado um bom desempenho do MO em identificar os sistemas, bem como algumas características associadas, tais como: número de ocorrência, número de dias com atuação, posicionamento, direção de deslocamento e região de formação.

scholarly journals Modelagem da maré meteorológica utilizando redes neurais artificiais: uma aplicação para a Baía de Paranaguá-PR, parte 2: dados meteorológicos de reanálise do NCEP/NCAR

2007 ◽  
Vol 22 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Marilia Mitidieri F. de Oliveira ◽  
Nelson Francisco F. Ebecken ◽  
Isimar de A. Santos ◽  
Claudio F. Neves ◽  
Luiz P. Caloba ◽  
...  
Keyword(s):  
Atmospheric Research ◽  
Environmental Prediction

A variabilidade do nível do mar observado e a maré meteorológica na Baía de Paranaguá-PR foram analisadas, neste trabalho, com os dados maregráficos utilizados na Parte 1 e os dados meteorológicos de reanálise do "National Centers for Environmental Prediction" (NCEP) e do "National Center Atmospheric Research" (NCAR) pontos de grade no oceano, próximos ao local de estudo, referentes ao mesmo período. As componentes de alta freqüência contidas nos dados de reanálise foram retiradas com o filtro passa-baixa de Thompson, descrito na Parte 1, adaptado para intervalos de 6 horas. Analisou-se as influências das variáveis meteorológicas mais remotas, nas sobre-elevações e abaixamentos do nível do mar observado, utilizando dados de reanálise de pressão e vento. Conforme descrito na Parte 1, as séries foram analisadas, estatisticamente, no domínio do tempo e da freqüência. A série maregráfica filtrada de Cananéia (SP), utilizada para verificar a existência de correlação com a série de Paranaguá, confirmou os estudos de Mesquita (1997) para o litoral Sudeste. Essa correlação foi verificada devido à proximidade da estação de Cananéia ao ponto de grade relativo à pressão. A Rede Neural Artificial (RNA) desenvolvida na Parte 1 foi, então, utilizada com os dados de reanálise, mantendo-se a mesma arquitetura de rede com as máximas correlações entre as variáveis de entrada e saída, ajustando-se os parâmetros de taxa de aprendizado e momento para alcançar o melhor desempenho. Os resultados obtidos com ambas as fontes de dados foram comparados e a eficiência da rede foi semelhante à Parte 1 para as simulações de 6h e 12 h. Para as simulações de 18h e 24h, os resultados foram inferiores como os encontrados para a estação de superfície, sugerindo também, o desenvolvimento de outras arquiteturas de rede, visando melhorar as previsões para períodos maiores. Os resultados obtidos com os dados de reanálise sugerem a sua utilização na falta de estações meteorológicas convencionais próximas a estações maregráficas.

scholarly journals Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling

2013 ◽  
Vol 9 (1) ◽  
pp. 119-133 ◽  
Author(s):  
D. Mottaghy ◽  
G. Schwamborn ◽  
V. Rath
Keyword(s):  
Surface Temperature ◽  
Thermal Regime ◽  
Climate Changes ◽  
Ground Surface ◽  
Temperature Data ◽  
Ice Age ◽  
Drilling Process ◽  
Past Climate ◽  
Ground Surface Temperature ◽  
Recent Climate

Abstract. This study focuses on the temperature field observed in boreholes drilled as part of interdisciplinary scientific campaign targeting the El'gygytgyn Crater Lake in NE Russia. Temperature data are available from two sites: the lake borehole 5011-1 located near the center of the lake reaching 400 m depth, and the land borehole 5011-3 at the rim of the lake, with a depth of 140 m. Constraints on permafrost depth and past climate changes are derived from numerical simulation of the thermal regime associated with the lake-related talik structure. The thermal properties of the subsurface needed for these simulations are based on laboratory measurements of representative cores from the quaternary sediments and the underlying impact-affected rock, complemented by further information from geophysical logs and data from published literature. The temperature observations in the lake borehole 5011-1 are dominated by thermal perturbations related to the drilling process, and thus only give reliable values for the lowermost value in the borehole. Undisturbed temperature data recorded over more than two years are available in the 140 m deep land-based borehole 5011-3. The analysis of these observations allows determination of not only the recent mean annual ground surface temperature, but also the ground surface temperature history, though with large uncertainties. Although the depth of this borehole is by far too insufficient for a complete reconstruction of past temperatures back to the Last Glacial Maximum, it still affects the thermal regime, and thus permafrost depth. This effect is constrained by numerical modeling: assuming that the lake borehole observations are hardly influenced by the past changes in surface air temperature, an estimate of steady-state conditions is possible, leading to a meaningful value of 14 ± 5 K for the post-glacial warming. The strong curvature of the temperature data in shallower depths around 60 m can be explained by a comparatively large amplitude of the Little Ice Age (up to 4 K), with low temperatures prevailing far into the 20th century. Other mechanisms, like varying porosity, may also have an influence on the temperature profile, however, our modeling studies imply a major contribution from recent climate changes.

Phenological behaviour of early spring flowering trees in Spain in response to recent climate changes

2017 ◽  
Vol 132 (1-2) ◽  
pp. 263-273 ◽  
Author(s):  
M. D. Hidalgo-Galvez ◽  
H. García-Mozo ◽  
J. Oteros ◽  
A. Mestre ◽  
R. Botey ◽  
...  
Keyword(s):  
Climate Changes ◽  
Early Spring ◽  
Recent Climate

scholarly journals Validation of the Aura High Resolution Dynamics Limb Sounder geopotential heights

2014 ◽  
Vol 7 (2) ◽  
pp. 1001-1025
Author(s):  
L. L. Smith ◽  
J. C. Gille
Keyword(s):  
High Resolution ◽  
System Model ◽  
Weather Forecasts ◽  
Atmospheric Research ◽  
Earth Observing System ◽  
Medium Range ◽  
High Bias ◽  
Environmental Prediction ◽  
The Tropics ◽  
Data Screening

Abstract. Global satellite observations from the EOS Aura spacecraft's High Resolution Dynamics Limb Sounder (HIRDLS) of temperature and geopotential height (GPH) are discussed. The accuracy, resolution and precision of the HIRDLS version 7 algorithms are assessed and data screening recommendations are made. Comparisons with GPH from observations, reanalyses and models including European Center for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim), National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis, Goddard Earth Observing System Model (GEOS) version 5, and EOS Aura Microwave Limb Sounder (MLS) illustrate the HIRDLS GPH have a precision ranging from 2 m to 30 m and an accuracy of ±100 m. Comparisons indicate HIRDLS GPH may have a slight low bias in the tropics and a slight high bias at high latitudes. Geostrophic winds computed with HIRDLS GPH qualitatively agree with winds from other data sources including ERA-Interim, NCEP and GEOS-5.

Recent climate changes over the Tibetan Plateau and their impacts on energy and water cycle: A review

2014 ◽  
Vol 112 ◽  
pp. 79-91 ◽  
Author(s):  
Kun Yang ◽  
Hui Wu ◽  
Jun Qin ◽  
Changgui Lin ◽  
Wenjun Tang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Climate Changes ◽  
Water Cycle ◽  
The Tibetan Plateau ◽  
Recent Climate

scholarly journals Stratospheric semi-decadal oscillations in NCEP data

2008 ◽  
Vol 26 (8) ◽  
pp. 2143-2157 ◽  
Author(s):  
H. G. Mayr ◽  
J. G. Mengel ◽  
F. T. Huang ◽  
E. R. Talaat ◽  
E. R. Nash ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Data Analysis ◽  
Temperature Data ◽  
Spectral Features ◽  
Altitude Range ◽  
Quasi Biennial Oscillation ◽  
Atmospheric Research ◽  
Zonal Winds ◽  
Environmental Prediction ◽  
Biennial Oscillation

Abstract. An analysis of the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) data is presented to provide a more complete description of the stratospheric 5-year semi-decadal (SD) oscillation (Mayr et al., 2007). The zonal-mean temperature and zonal wind data from the Atmospheric Research R-1 analysis are employed, covering the years from 1962 to 2002 in the altitude range from 10 to 30 km. For diagnostic purposes, the data are separated into the hemispherically symmetric and anti-symmetric components, and spectral analysis is applied to identify the signatures of the SD oscillations. Through the synthesis or filtering of spectral features, the SD modulations of the annual oscillation (AO) and quasi-biennial oscillation (QBO) are delineated. In agreement with the earlier findings, the magnitude of the SD oscillation is more pronounced when the 30-month QBO dominates during the years from 1975 to 1995. This is consistent with results from a numerical model, which shows that such a QBO generates the SD oscillation through interaction with the 12-month AO. In the zonal winds, the SD oscillation in the NCEP data is confined to equatorial latitudes, where it modulates the symmetric AO and QBO by about 5 m/s below 30 km. In the temperature data, the effect is also seen around the equator, but it is much larger at polar latitudes where the SD oscillation produces variations as large as 2 K. Our data analysis indicates that the SD oscillation is mainly hemispherically symmetric, and it appears to originate at equatorial latitudes where most of the energy resides.

Simulating the response of a closed-basin lake to recent climate changes in tropical West Africa (Lake Bosumtwi, Ghana)

2007 ◽  
Vol 21 (13) ◽  
pp. 1678-1691 ◽  
Author(s):  
Timothy M. Shanahan ◽  
Jonathan T. Overpeck ◽  
W. E. Sharp ◽  
Christopher A. Scholz ◽  
Justice A. Arko
Keyword(s):  
West Africa ◽  
Climate Changes ◽  
Closed Basin ◽  
Recent Climate

scholarly journals Stock fluctuations of the Japanese common squid, Todarodes pacificus, related to recent climate changes

2002 ◽  
Vol 68 (sup1) ◽  
pp. 226-229 ◽  
Author(s):  
Yasunori SAKURAI ◽  
Hidetada KIYOFUJI ◽  
Sei-ichi SAITOH ◽  
Jun YAMAMOTO ◽  
Tsuneo GOTO ◽  
...  
Keyword(s):  
Climate Changes ◽  
Todarodes Pacificus ◽  
Common Squid ◽  
Recent Climate ◽  
Japanese Common Squid

scholarly journals Arctic precipitation as represented in the NCEP/NCAR reanalysis

1997 ◽  
Vol 25 ◽  
pp. 429-433 ◽  
Author(s):  
Mark C. Serreze ◽  
James A. Maslanik
Keyword(s):  
Sea Ice ◽  
Temporal Patterns ◽  
Annual Precipitation ◽  
Model Output ◽  
Atmospheric Research ◽  
Spatio Temporal ◽  
Environmental Prediction ◽  
Climate Studies

Arctic precipitation as depicted in the National Center for Environmental Prediction (NGEP) and the National Center for Atmospheric Research (NCAR) reanalysis effort is evaluated using 6 hourly model output for the period 1986–93 in conjunction with gauge-corrected climatologies. Climatological fields from the model agree favorably with observations in terms of general spatio-temporal patterns, but with some notable differences. In particular, the precipitation maximum over the central Arctic (the region north of 70°N) is depicted in July, one month too early. Values are too low from August through December, resulting in underestimates of annual precipitation of about 40 mm. Despite these shortcomings, the modeled precipitation fields appear to be sufficiently realistic to represent a base for blending with other data to provide gridded fields suitable for use in climate studies and sea-ice models.

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