The Twentieth Century Reanalysis Project Compo, G. P.; Whitaker, J. S.; Sardeshmukh, P. D. ...
Quarterly journal of the Royal Meteorological Society,
January 2011 Part A, 2011, 2011-01-00, 20110101, 2011-01-01, Letnik:
137, Številka:
654
Journal Article
Background In July 2006, a lasting and severe heat wave occurred in Western Europe. Since the 2003 heat wave, several preventive measures and an alert system aiming at reducing the risks related to ...high temperatures have been set up in France by the health authorities and institutions. In order to evaluate the effectiveness of those measures, the observed excess mortality during the 2006 heat wave was compared to the expected excess mortality. Methods A Poisson regression model relating the daily fluctuations in summer temperature and mortality in France from 1975 to 2003 was used to estimate the daily expected number of deaths over the period 2004–2006 as a function of the observed temperatures. Results During the 2006 heat wave (from 11 to 28 July), about 2065 excess deaths occurred in France. Considering the observed temperatures and with the hypothesis that heat-related mortality had not changed since 2003, 6452 excess deaths were predicted for the period. The observed mortality during the 2006 heat wave was thus markedly less than the expected mortality (∼4400 less deaths). Conclusions The excess mortality during the 2006 heat wave, which was markedly lower than that predicted by the model, may be interpreted as a decrease in the population's vulnerability to heat, together with, since 2003, increased awareness of the risk related to extreme temperatures, preventive measures and the set-up of the warning system.
The diurnal cycle of the West African monsoon circulation Parker, D. J.; Burton, R. R.; Diongue‐Niang, A. ...
Quarterly journal of the Royal Meteorological Society,
October 2005 Part A, Letnik:
131, Številka:
611
Journal Article
THE COMPREHENSIVE HISTORICAL UPPER-AIR NETWORK Stickler, A.; Grant, A. N.; Ewen, T. ...
Bulletin of the American Meteorological Society,
06/2010, Letnik:
91, Številka:
6
Journal Article
Recenzirano
Odprti dostop
To better understand variability in weather and climate, it is vital to address past atmospheric circulation. This need requires meteorological information not just from the surface but also at upper ...levels. Current global upper-level datasets only reach back to the 1940s or 1950s and do not cover some important periods in the first half of the twentieth century. Extending the observational record is therefore considered important in order to analyze climate variability in the past and verify global climate models used to predict future climate change. Although earlier upper-air data from platforms such as radiosondes, aircraft, pilot balloons, registering balloons, and kites are available from various sources, no systematic compilation and quality assessment of upper-level data prior to the International Geophysical Year (1957/58) has ever been performed. Here we present the Comprehensive Historical Upper-Air Network (CHUAN). It is a consistent global historical upper-air dataset that has been derived from heterogeneous data available from various sources as well as from newly digitized data. This paper describes the CHUAN dataset, the metadata, the quality control procedures, and the relationship to existing datasets. Some examples are given of its usefulness for analyzing weather and climate during the first half of the twentieth century. The CHUAN dataset comprises 3987 station records worldwide or about 16.4 million profiles (of which 12.6 million are before 1958 and 5.3 million, primarily from pilot balloons, are before 1948). A monthly mean version can be downloaded from the World Wide Web (www.historicalupperair.org).
The Hydrologic Atmospheric Pilot EXperiment in the Sahel (HAPEX-Sahel) was carried out in Niger, West Africa, during 1991 - 1992, with an intensive observation period (IOP) in August - October 1992. ...It aims at improving the parameterization of land surface atmosphere interactions at the Global Circulation Model (GCM) gridbox scale. The experiment combines remote sensing and ground based measurements with hydrological and meteorological modelling to develop aggregation techniques for use in large scale estimates of the hydrological and meteorological behaviour of large areas in the Sahel. The experimental strategy consisted of a period of intensive measurements during the transition period of the rainy to the dry season, backed up by a series of long term measurements in a 1° by 1° square in Niger. Three "supersites" were instrumented with a variety of hydrological and (micro) meteorological equipment to provide detailed information on the surface energy exchange at the local scale. Boundary layer measurements and aircraft measurements were used to provide information at scales of 100 - 500 km2. All relevant remote sensing images were obtained for this period. This programme of measurements is now being analyzed and an extensive modelling programme is under way to aggregate the information at all scales up to the GCM grid box scale. The experimental strategy and some preliminary results of the IOP are described.
On 13 September 1922, a temperature of 58°C (136.4°F) was purportedly recorded at El Azizia (approximately 40 km south-southwest of Tripoli) in what is now modern-day Libya. That temperature record ...of 58°C has been cited by numerous world-record sources as the highest recorded temperature for the planet. During 2010–11, a World Meteorological Organization (WMO) Commission of Climatology (CCl) special international panel of meteorological experts conducted an in-depth investigation of this record temperature for the WMO World Archive of Weather and Climate Extremes (http://wmo.asu.edu/). This committee identified five major concerns with the 1922 El Azizia temperature extreme record, specifically 1) potentially problematical instrumentation, 2) a probable new and inexperienced observer at the time of observation, 3) unrepresentative microclimate of the observation site, 4) poor correspondence of the extreme to other locations, and 5) poor comparison to subsequent temperature values recorded at the site. Based on these concerns, the WMO World Archive of Weather and Climate Extremes rejected this temperature extreme of 58°C as the highest temperature officially recorded on the planet. The WMO assessment is that the highest recorded surface temperature of 56.7°C (134°F) was measured on 10 July 1913 at Greenland Ranch (Death Valley), California.
The variability between surface flux measurements at the fallow sites of the three HAPEX-Sahel supersites is examined over periods of three or four consecutive days. A roving eddy correlation ...instrument provided a common base for comparison at each supersite. The inhomogeneity of the surface and the instrumental layout did not provide the conditions to allow the separation of the effects of instrument error from those due to the spatial variability of vegetation cover and soil moisture. Surface fluxes of sensible and latent heat and energy balance terms were intercompared at each supersite over summation timescales of 1 hour and 3 days. It is shown that, generally, HAPEX-Sahel hourly sensible heat flux and latent heat values have confidence limits of 15% and 20% respectively. The three-day period energy balance shows the combined sensible and latent heat fluxes to have a confidence limit of 3%. It is concluded that, due to the averaging effect of longer time periods and larger flux footprints on spatial inhomogeneity, confidence in the surface flux measurements increases with longer summation periods and with neutral atmospheric surface layers which characterise the rainy period of the Intensive Observation Period.
Hapex Sahel (Hydrologic Atmospheric Pilot Experiment in the Sahel) was an international program focused on the soil-plant-atmosphere energy, water and carbon balance in the west African Sahel. It was ...intended to improve our understanding of the interaction between the Sahel and the general atmospheric circulation, both at present and in the future, providing a base line for studies of climate change. It was carried out in a 1° × 1° area of west Niger over a 3–4 year period with an 8-week intensive observation period from August to October 1992. HAPEX-Sahel was funded by a wide range of agencies in seven participating countries. Over 170 scientists visited and worked in the field. An interdisciplinary approach was adopted with contributed studies in hydrology and soil moisture, surface fluxes and vegetation, remote sensing science, and meteorology and mesoscale modeling. Detailed field measurements were concentrated at 3 “supersites” and 3 ancillary sites. Four aircraft were used for remote sensing and flux measurement. Observations from space were acquired from nine sensors on seven different satellite platforms. Conditions in 1992 turned out to be average for the last decade with good gradients of precipitation and a variety of vegetation productivities between the study sites. An information system has been established to provide a data base to disseminate the measurements. An active program of meetings, workshops, and interdisciplinary studies is now in progress.
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