6 research outputs found
A HIGH RESOLUTION TEMPERATURE CLIMATOLOGY FOR THE GREATER ALPINE REGION (GAR)
No full textThe Greater Alpine Region (the GAR) covering the area between 4-19°E and 43-50°N and an altitude range between 0 and more than 4000 m asl. offers a challenging climate worth to be studied in any detail. However, it is surprising that up to now no comprehensive Alpine Temperature Climatology covering the whole region is existing. To overcome this deficiency as a first step we want to produce monthly temperature maps for this region in spatial resolution as high as possible. The period under investigation will be 1961-1990. In this paper we will describe the first steps of our initiative as well as the further plans
HISTALP - historical instrumental climatological surface time series for the Greater Alpine Region
No full textThis paper describes the HISTALP database, consisting of monthly homogenised records of temperature, pressure, precipitation, sunshine and cloudiness for the 'Greater Alpine Region' (GAR, 4-19 degrees E, 43-49 degrees N, 0-3500m asl). The longest temperature and air pressure series extend back to 1760, precipitation to 1800, cloudiness to the 1840s and sunshine to the 1880s. A systematic QC procedure has been applied to the series and a high number of inhomogeneities (more than 2500) and outliers (more than 5000) have been detected and removed. The 557 HISTALP series are kept in different data modes: original and homogenised, gap-filled and outlier corrected station mode series, grid-1 series (anomaly fields at 1 degrees *1 degrees , lat * long) and Coarse Resolution Subregional (CRS) mean series according to an EOF-based regionalisation. The leading climate variability features within the GAR are discussed through selected examples and a concluding linear trend analysis for 100, 50 and 25-year subperiods for the four horizontal and two altitudinal CRSs. Among the key findings of the trend analysis is the parallel centennial decrease/increase of both temperature and air pressure in the 19th/20th century. The 20th century increase (+1.2 degrees C/+1.1 hPa for annual GAR-means) evolved stepwise with a first peak near 1950 and the second increase (1.3 degrees C/0.6hPa per 25 years) starting in the 1970s. Centennial and decadal scale temperature trends were identical for all subregions. Air pressure, sunshine and cloudiness show significant differences between low versus high elevations. A long-term increase of the high-elevation series relative to the low-elevation series is given for sunshine and air pressure. Of special interest is the exceptional high correlation near 0.9 between the series on mean temperature and air pressure difference (high-minus low-elevation). This, further developed via some atmospheric statics and thermodynamics, allows the creation of 'barometric temperature series' without use of the measures of temperature. They support the measured temperature trends in the region. Precipitation shows the most significant regional and seasonal differences with, e.g., remarkable opposite 20th century evolution for NW (9% increase) versus SE (9% decrease). Other long- and short-term features are discussed and indicate the promising potential of the new database for further analyses and applications
Potential climatic transitions with profound impact on Europe
No full textWe discuss potential transitions of six climatic subsystems with large-scale impact on Europe, sometimes denoted as tipping elements. These are the ice sheets on Greenland and West Antarctica, the Atlantic thermohaline circulation, Arctic sea ice, Alpine glaciers and northern hemisphere stratospheric ozone. Each system is represented by co-authors actively publishing in the corresponding field. For each subsystem we summarize the mechanism of a potential transition in a warmer climate along with its impact on Europe and assess the likelihood for such a transition based on published scientific literature. As a summary, the ‘tipping’ potential for each system is provided as a function of global mean temperature increase which required some subjective interpretation of scientific facts by the authors and should be considered as a snapshot of our current understanding. <br/
Correlation of Glacier ELA/Snowlines & Temperature Station data with ERA5 Temperature and Wind Speed, 1979 to 2017
No full textThis dataset contains the gridded correlation results from a study that sought to better understand the climatic footprint monitored by antipodal mid-latitude glacier populations. Understanding the links between glaciers and climate is critical for accurately interpreting contemporary cryosphere changes, and interrogating the causes of past glacier behavior. However, work is still needed to refine the extent to which they capture regional to hemisphere-scale atmospheric processes. A Pearson's correlation was performed between yearly summer seasonal data from the ERA5 gridded reconstructions of global temperature and wind changes on each available ERA5 pressure level and yearly glacier snowline/ELA elevations in the Southern Alps of New Zealand and in the European Alps. December-Febuary austral summer data was correlated with the Southern Alps records and June-August Northern Hemisphere summer data was correlated with the European Alps. The ERA5 input dataset was regridded onto a new monthly axis representing the true month lengths. Then the weighted seasonal average (December-February and June-August) was calculated. Individuals glaciers with Equilibrium Line Altitude (ELA; European Alps) and End of Summer Snowlines (EOSS; Southern Alps) were selected with respective records covering at least 80% of the 1979-2017/15 analysis period. The records from each glacier were then standardized and an EOF analysis was performed to obtain each location's First Principle Component for input into the Pearson's Correlation.
A nearly identical set of analyses was performed using weather stations temperature data instead of glacier ELA/snowlines. The New Zealand station equivalent is from the National Institute of Water and Atmospheric Research (NIWA) New Zealand seven-station (NZ7S) series. The European Alps equivalent is from the HistAlp regional weather station syntheses. This companion analysis allows the glacier's ability to record the climate to be compared to that of meteorological instruments
Global Early Instrumental Monthly Meteorological Multivariable Database (HCLIM)
No full textThere is a growing need for past weather and climate data to support science and decision-making. This paper describes the compilation and the construction of a global multivariable (air temperature, pressure, precipitation sum, number of precipitation days) monthly instrumental climate database that encompasses a substantial body of the known early instrumental time series. The dataset contains series compiled from existing databases that start before 1890 (though continuing to the present) as well as a large amount of newly rescued data. All series underwent a quality control procedure and subdaily series were processed to monthly mean values. An inventory was compiled, and the collection was deduplicated based on coordinates and mutual correlations. The data are provided in a common format accompanied by the inventory. The collection totals 12452 meteorological records in 118 countries. The data has been merged from 18250 original data files. The data can be used for climate reconstructions and analyses. It is the most comprehensive global monthly climate data set for the preindustrial period
