M. Kottek’s research while affiliated with GeoSphere Austria and other places

The classical paper of Köppen (1884a) on “The thermal zones of the Earth according to the duration of hot, moderate and cold periods and of the impact of heat on the organic world”, published in the first volume of the Meteorologische Zeitschrift, is considered today as an early forerunner of the most widely used Köppen-Geiger climate classification. We depict the historical background of the evolution of Köppen's climate classification from the beginning in the early 19th century until the present. An overview on 21st century applications demonstrates the high scientific impact of Wladimir Köppen's historical work. German Die klassische Arbeit von Köppen (1884a) über ,,Die Wärmezonen der Erde, nach der Dauer der heissen, gemässigten und kalten Zeit und nach der Wirkung der Wärme auf die organische Welt betrachtet“, publiziert in der ersten Ausgabe der Meteorologischen Zeitschrift, wird heute als früher Vorläufer der weit verbreiteten Köppen-Geiger Klimaklassifikation betrachtet. Wir beleuchten den historischen Hintergrund der Entwicklung der Köppen'schen Klimaklassifikation von den Anfängen im frühen 19. Jhdt. bis zur Gegenwart. Ein Überblick der Anwendungen im 21. Jhdt. demonstriert die große wissenschaftliche Bedeutung der historischen Arbeit von Wladimir Köppen.

In a previous paper we presented an update of the highly referenced climate classification map, that of Wladimir Koppen, which was published for the first time in 1900 and updated in its latest version by Rudolf Geiger in 1961. This updated world map of Koppen-Geiger climate classification was based on temperature and precipitation observations for the period 1951-2000. Here, we present a series of digital world maps for the extended period 1901-2100 to depict global trends in observed climate and projected climate change scenarios. World maps for the observational period 1901-2002 are based on recent data sets from the Climatic Research Unit (CRU) of the University of East Anglia and the Global Precipitation Climatology Centre (GPCC) at the German Weather Service. World maps for the period 2003-2100 are based on ensemble projections of global climate models provided by the Tyndall Centre for Climate Change Research. The main results comprise an estimation of the shifts of climate zones within the 21st century by considering different IPCC scenarios. The largest shifts between the main classes of equatorial climate (A), arid climate (B), warm temperate climate (C), snow climate (D) and polar climate (E) on global land areas are estimated as 2.6-3.4 % (E to D), 2.2-4.7 % (D to C), 1.3-2.0 (C to B) and 2.1-3.2 % (C to A).

Global daily precipitation analyses are mainly based on satellite estimates, often cal-ibrated with monthly ground analyses or merged with model predictions. We argue here that an essential improvement of their accuracy is only possible by incorporation of daily ground measurements. Here we present geostatistical methods to compile a global precipitation product based on daily rain gauge measurements. The raw ground measurements, disseminated via GTS, are corrected for their systematic measurement errors [1] and interpolated onto a global 1 degree grid [2]. For interpolation ordinary block kriging is applied, with precalculated spatial auto-correlation functions (ACFs). This technique allows to in-corporate additional climate information. First, monthly ACFs are calculated from the daily data; second, they are regionalised according to the 5 main climatic zones of an updated Köppen-Geiger climate classification [3], provided at http://koeppen-geiger.vu-wien.ac.at. The interpolation error, a by-product of kriging, is used to flag grid points as missing if the error is above a predefined threshold. But for many ap-plications missing values constitute a problem. Due to a combination of the ground analyses with the daily multi-satellite product of the Global Precipitation Climatology Project (GPCP-1DD) not only these missing values are replaced but also the spatial structure of the satellite estimates is considered. As merging method bivariate ordi-nary co-kriging is applied. The ACFs necessary for the gauge and the satellite fields as well as the corresponding spatial cross-correlation functions (CCFs) are again pre-calculated for each of the 5 main climatic zones and for each individual month. As a result two new global daily data sets for the period 1996 to present will be avail-able on the Internet (http://precipitation.vu-wien.ac.at): A precipitation product over land, analysed from ground measurements; and a global precipitation product merged from this and the GPCP-1DD multi-satellite product. Both products show a significant improvement in terms of verification scores, compared to the original multi-satellite product. For example, the verification over the entire European Union results in a rank-order correlation coefficient which increases from 0.49 (GPCP-1DD) to 0.86 (merged product). The true skill score (TSS) increases from 0.36 (GPCP-1DD) to 0.67 (merged product). Detailed verification results over Europe, East Asia and Australia will be presented in [4].

Global daily precipitation analyses are mainly based on satellite estimates, often calibrated with monthly ground analyses or merged with model predictions. We argue here that an essential improvement of their accuracy is only possible by incorporation of daily ground measurements. In this work we apply geostatistical methods to compile a global precipitation product based on daily rain gauge measurements. The raw ground measurements, disseminated via Global Telecommunication System (GTS), are corrected for their systematic measurement errors and interpolated onto a global 1 degree grid. For interpolation ordinary block kriging is applied, with precalculated spatial auto-correlation functions (ACFs). This technique allows to incorporate additional climate information. First, monthly ACFs are calculated from the daily data; second, they are regionalised according to the five main climatic zones of the Köppen-Geiger climate classification. The interpolation error, a by-product of kriging, is used to flag grid points as missing if the error is above a predefined threshold. But for many applications missing values constitute a problem. Due to a combination of the ground analyses with the daily multi-satellite product of the Global Precipitation Climatology Project (GPCP-1DD) not only these missing values are replaced but also the spatial structure of the satellite estimates is considered. As merging method bivariate ordinary co-kriging is applied. The ACFs necessary for the gauge and the satellite fields as well as the corresponding spatial cross-correlation functions (CCFs) are again precalculated for each of the five main climatic zones and for each individual month. As a result two new global daily data sets for the period 1996 up to today will be available on the Internet (www.gmes-geoland.info): A precipitation product over land, analysed from ground measurements; and a global precipitation product merged from this and the GPCP-1DD multi-satellite product.

The most frequently used climate classification map is that of Wladimir Köppen, presented in its latest version 1961 by Rudolf Geiger. A huge number of climate studies and subsequent publications adopted this or a former release of the Köppen-Geiger map. While the climate classification concept has been widely applied to a broad range of topics in climate and climate change research as well as in physical geography, hydrology, agriculture, biology and educational aspects, a well-documented update of the world climate classification map is still missing. Based on recent data sets from the Climatic Research Unit (CRU) of the University of East Anglia and the Global Precipitation Climatology Centre (GPCC) at the German Weather Service, we present here a new digital Köppen-Geiger world map on climate classification, valid for the second half of the 20 century. German Die am häufigsten verwendete Klimaklassifikationskarte ist jene von Wladimir Köppen, die in der letzten Auflage von Rudolf Geiger aus dem Jahr 1961 vorliegt. Seither bildeten viele Klimabücher und Fachartikel diese oder eine frühere Ausgabe der Köppen-Geiger Karte ab. Obwohl das Schema der Klimaklassifikation in vielen Forschungsgebieten wie Klima und Klimaänderung aber auch physikalische Geographie, Hydrologie, Landwirtschaftsforschung, Biologie und Ausbildung zum Einsatz kommt, fehlt bis heute eine gut dokumentierte Aktualisierung der Köppen-Geiger Klimakarte. Basierend auf neuesten Datensätzen des Climatic Research Unit (CRU) der Universität von East Anglia und des Weltzentrums für Niederschlagsklimatologie (WZN) am Deutschen Wetterdienst präsentieren wir hier eine neue digitale Köppen-Geiger Weltkarte für die zweite Hälfte des 20. Jahrhunderts.

Consistent and validated data sets of satellite‐borne radiances and of a large variety of products describing the characteristics of terrestrial cloud and radiation fields have been produced within the International Satellite Cloud Climatology Project (ISCCP) covering the years 1983 through to 2003. A subset (annual and seasonal averages of the 5 year period 1991 to 1995) is used in this paper to discuss in greater detail the effect of clouds on the radiation fields at the upper and lower boundary of the atmosphere and in particular on the loss and gain (vertical divergence) of radiant energy by the atmosphere itself. Although this subset covers the effects of the Pinatubo eruption (June 1991) and of the strong El Niño event in 1992–93, which indeed caused ‘anomalies in the average aerosol and cloud fields in the tropics and subtropics’. However, our regional averages of the radiation budget at the top of the atmosphere and at ground over a period of 5 years should be within 2–5 W m ⁻² of longer term averages. We find very interesting spatial patterns in the global distributions of all quantities, which can be explained in part by various cloud field characteristics and by the continental surface characteristics. Most are known from similar studies with radiation budget measurements. Possibly for the first time, we show global fields of the vertical flux divergence of solar and terrestrial radiation within the atmosphere and of the effects of clouds. Both polar regions, various portions of China and the areas of persistent subtropical maritime stratocumulus fields over the Pacific and Atlantic Oceans and of cloud fields associated with the intertropical convergence zone (ITCZ) offer specific features for further analyses. This ISCCP data set seems to underestimate the absorption of solar radiation in the tropical and subtropical atmosphere by about 10 to 20 W m ⁻² . There is a disagreement of about 30 W m ⁻² in global averages of the gain and loss of solar and terrestrial radiation in the atmosphere between this and two other independent data sets, which needs thorough investigation, since such data are required to validate the radiation budgets within circulation and climate models and for other climate studies. Such an assessment of radiation budget data is now under way within the auspices of the World Climate Research Programme. Copyright © 2005 Royal Meteorological Society

This document is part of Volume 6 'Observed Global Climate' of Landolt-Börnstein - Group V Geophysics. 3 Data management (Part 1/2) 3.1 Introduction 3.2 The digital data archive 3.3 Selected features of the global climate depicted in the animate data 3.3.1 The South Pacific convergence zone (SPCZ)