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Surface Temperature Anomalies (surface + temperature_anomaly)
Kinds of Surface Temperature Anomalies Selected AbstractsMulti-annual dry episodes in Australian climatic variabilityINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 12 2009B. G. Hunt Abstract The output from a 10 000-year simulation with the CSIRO Mark 2 coupled global climatic model has been analysed to investigate the occurrence of multi-year dry episodes for three selected regions of Australia, specifically, the northeast, southeast and southwest of the continent. Results are presented for dry episodes lasting for 8 or more years. An episode is defined as a time interval having consecutive negative rainfall anomalies, but not necessarily a major drought, for each year of the episode. The hydrological consequences of such an episode can persist for over a century. Typically about 30 episodes are found over the 10 000 years of the simulation for each of the three regions. There is little synchronicity between the regions in the occurrence of the dry episodes. While there is an El Nino/Southern Oscillation (ENSO) influence associated with these episodes, it is not continuous over the duration of an episode. Composites of sea surface temperature anomalies over an episode highlight the limited presence of ENSO events. The occurrence of the dry episodes for all three regions is essentially random, with multi-centennial periods without an episode, and episodes at multi-decadal frequency at other times. Following a discussion of possible mechanistic influences, it is concluded that stochastic forcing is responsible for the occurrence of dry episodes. This implies that there is no predictability associated with the initiation, duration or termination of individual dry episodes. This also suggests that the 2000,2007 dry episodes occurring over much of Australia may not be caused by the greenhouse effect. Such an episode has a return period of between 200 and 300 years based on the mean frequency of occurrence in the present simulation. Copyright © 2008 Royal Meteorological Society [source] Europe's 2003 heat wave: a satellite view of impacts and land,atmosphere feedbacksINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2006Benjamin F. Zaitchik Abstract A combination of satellite imagery, meteorological station data, and the NCEP/NCAR reanalysis has been used to explore the spatial and temporal evolution of the 2003 heat wave in France, with focus on understanding the impacts and feedbacks at the land surface. Vegetation was severely affected across the study area, especially in a swath across central France that corresponds to the Western European Broadleaf (WEB) Forests ecological zone. The remotely sensed surface temperature anomaly was also greatest in this zone, peaking at +15.4 °C in August. On a finer spatial scale, both the vegetation and surface temperature anomalies were greater for crops and pastures than for forested lands. The heat wave was also associated with an anomalous surface forcing of air temperature. Relative to other years in record, satellite-derived estimates of surface-sensible heat flux indicate an enhancement of 48,61% (24.0,30.5 W m,2) in WEB during the August heat wave maximum. Longwave radiative heating of the planetary boundary layer (PBL) was enhanced by 10.5 W m,2 in WEB for the same period. The magnitude and spatial structure of this local heating is consistent with models of the late twenty-first century climate in France, which predict a transitional climate zone that will become increasingly affected by summertime drought. Models of future climate also suggest that a soil-moisture feedback on the surface energy balance might exacerbate summertime drought, and these proposed feedback mechanisms were tested using satellite-derived heat budgets. Copyright © 2006 Royal Meteorological Society. [source] Seasonal modulation of the El Niño,southern oscillation relationship with sea level pressure anomalies over the North Atlantic in October,March 1873,1996INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2003V. Moron Abstract The seasonal modulation of the relationship between the sea-level pressure anomalies (SLPAs) over the North Atlantic region (100°W,50°E; 20,70°N) and the sea surface temperature anomalies (SSTAs) in the tropical Pacific (120,290°E; 20°N,20°S) is investigated in the northern winter (October to March) from 1873 to 1996, using singular-value decomposition and composite analyses. Both methods show that the pattern of the North Atlantic SLPA associated with the tropical Pacific SSTA in November,December is different from that found in January,March. The surface covered by a significant SLPA is larger in November,December and February,March than in January. In November,December, the warm El Niño,southern oscillation (ENSO) events are associated with negative SLPAs extending from the Hudson Bay to Scandinavia and positive SLPAs over the Azores high. The cold ENSO events are associated with a positive SLPA between Greenland and western Europe. In January, and mainly in February,March, the warm ENSO events are associated with a positive SLPA north of 50°N and a negative SLPA extending from the southeastern USA toward western and central Europe. The cold ENSO events exhibit almost reversed SLPA patterns. The change between November,December and January,March is also observed at the hemispheric scale. In November,December, the SLPAs associated with the warm minus cold ENSO composite form a hemispheric north,south dipole pattern with positive (negative) anomalies south (north) of 40,45°N. In January,March, the SLPA pattern associated with the warm minus cold ENSO composite is close to the tropical Northern-Hemisphere pattern. Copyright © 2003 Royal Meteorological Society. [source] The Pacific,South American modes and their downstream effectsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2001Kingtse C. Mo Abstract There are two pervasive modes of atmospheric variability in the Southern Hemisphere (SH) that influence circulation and rainfall anomalies over South America. They appear as leading empirical orthogonal functions (EOFs) of 500-hPa height or 200-hPa streamfunction anomalies and are found from intraseasonal to decadal time scales. Both patterns exhibit wave 3 hemispheric patterns in mid to high latitudes, and a well-defined wave train with large amplitude in the Pacific,South American (PSA) sector. Therefore, they are referred to as the PSA modes (PSA1 and PSA2). PSA1 is related to sea surface temperature anomalies (SSTAs) over the central and eastern Pacific at decadal scales, and it is the response to El Niño,Southern Oscillation (ENSO) in the interannual band. The associated rainfall summer pattern shows rainfall deficits over northeastern Brazil and enhanced rainfall over southeastern South America similar to rainfall anomalies during ENSO. PSA2 is associated with the quasi-biennial component of ENSO, with a period of 22,28 months and the strongest connections occur during the austral spring. The associated rainfall pattern shows a dipole pattern with anomalies out of phase between the South Atlantic Convergence Zone (SACZ) extending from central South America into the Atlantic and the subtropical plains centred at 35°S. These two modes are also apparent in tropical intraseasonal oscillations for both summer and winter. Eastward propagation of enhanced convection from the Indian Ocean through the western Pacific to the central Pacific is accompanied by a wave train that appears to originate in the convective regions. The positive PSA1 pattern is associated with enhanced convection over the Pacific from 150°E to the date line. The convection pattern associated with PSA2 is in quadrature with that of PSA1. Both PSA modes are influenced by the Madden Julian Oscillation and influence rainfall over South America. Copyright © 2001 Royal Meteorological Society [source] Impacts of the basin-wide Indian Ocean SSTA on the South China Sea summer monsoon onsetINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 12 2008Yuan Yuan Abstract This article explores the impacts of the Indian Ocean basin-scale sea surface temperature anomaly (SSTA) on the South China Sea (SCS) summer monsoon onset. Basin-wide warming in the tropical Indian Ocean (TIO) is found to occur in the spring following an El Niño event, and the opposite occurs for a La Niña event. Such changes of the Indian Ocean SSTA apparently prolong the El Niño-Southern Oscillation (ENSO) effects on the subsequent Asian summer monsoon, mainly through modifying the strength of the Philippine Sea anti-cyclone. Warming in the TIO induces an anomalous reversed Walker circulation over the tropical Indo,Pacific Ocean, which leads to descending motion, and hence suppressed convection in the western Pacific. The intensified Philippine Sea anti-cyclone in May and June advances more westward and prevents the extension of the Indian Ocean westerly flow into the SCS region, thereby causing a late SCS monsoon onset. The case is opposite for the TIO cooling such that the Philippine Sea anti-cyclone weakens and retreats eastward, thus favouring an early onset of the SCS monsoon. Copyright © 2008 Royal Meteorological Society [source] Europe's 2003 heat wave: a satellite view of impacts and land,atmosphere feedbacksINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2006Benjamin F. Zaitchik Abstract A combination of satellite imagery, meteorological station data, and the NCEP/NCAR reanalysis has been used to explore the spatial and temporal evolution of the 2003 heat wave in France, with focus on understanding the impacts and feedbacks at the land surface. Vegetation was severely affected across the study area, especially in a swath across central France that corresponds to the Western European Broadleaf (WEB) Forests ecological zone. The remotely sensed surface temperature anomaly was also greatest in this zone, peaking at +15.4 °C in August. On a finer spatial scale, both the vegetation and surface temperature anomalies were greater for crops and pastures than for forested lands. The heat wave was also associated with an anomalous surface forcing of air temperature. Relative to other years in record, satellite-derived estimates of surface-sensible heat flux indicate an enhancement of 48,61% (24.0,30.5 W m,2) in WEB during the August heat wave maximum. Longwave radiative heating of the planetary boundary layer (PBL) was enhanced by 10.5 W m,2 in WEB for the same period. The magnitude and spatial structure of this local heating is consistent with models of the late twenty-first century climate in France, which predict a transitional climate zone that will become increasingly affected by summertime drought. Models of future climate also suggest that a soil-moisture feedback on the surface energy balance might exacerbate summertime drought, and these proposed feedback mechanisms were tested using satellite-derived heat budgets. Copyright © 2006 Royal Meteorological Society. [source] Adverse meteorological phenomena associated with low-level baric troughs in the Alagoas State, Brazil, in 2003ATMOSPHERIC SCIENCE LETTERS, Issue 3 2010Luis Ricardo Lage Rodrigues Abstract Baric troughs were studied over the Alagoas State, Brazil, in 2003. The relationship between these synoptic systems, weekly sea surface temperature anomaly and adverse meteorological phenomena in the Alagoas State, was analyzed. The maximum trough frequency occurred at low levels during the wetter and colder season in the investigated region (June and July). Most of the troughs were observed at 1200 UTC. It was also noted that 87% of the troughs was associated with wavy disturbance in the trade winds on the northwestern periphery of the subtropical South Atlantic High. These troughs were associated with meteorological phenomena in a stable and an unstable atmosphere. Copyright © 2010 Royal Meteorological Society [source] | ||||||||||