Stephanie Hänsel

Precipitation Trend Analysis for Central Eastern Germany 1851–2006

Rising global temperatures are accompanied by precipitation changes. This relates to both total precipitation amounts, where an increase has to be expected, and to changing precipitation patterns. The latter being more spatially and seasonally variable than temperature change (IPCC 2007). Northern Europe is one of the regions that have become significantly wetter during the last century (IPCC 2007).

Assessing Homogeneity and Climate Variability of Temperature and Precipitation Series in the Capitals of North-Eastern Brazil

A 51-year dataset (1961 to 2011) from nine meteorological stations in the capitals of northeastern Brazil (NEB), with daily data of precipitation totals and of mean, minimum and maximum temperatures, was statistically analyzed for data homogeneity and for signals of climate variability. The hypothesis was explored that a connection exists between inhomogeneities of the time series and the meteorological systems influencing the region. Results of the homogeneity analysis depend on the selected test variable, the test algorithm and the chosen significance level; all more or less subjective choices. Most of the temperature series was classified as “suspect”, while most of the precipitation series was categorized as “useful”. Displaying and visually checking the time series demonstrates the power of expertise and may allow for a deeper data analysis. Consistent changes in the seasonality of temperature and precipitation emerge over NEB despite manifold breaks in the temperature series. Both series appear to be coupled. The intra-annual temperature and precipitation ranges have increased, along with an intensified seasonal cycle. Temperature mainly increased during DJF, MAM and SON, with decreases in JJA being related to wetter conditions and more frequent heavy precipitation events. Drought conditions mostly increased in SON and DJF, depending on the timing of the local dry season.

The Modified Rainfall Anomaly Index (mRAI)—is this an alternative to the Standardised Precipitation Index (SPI) in evaluating future extreme precipitation characteristics?

Precipitation extremes affect various economic sectors and may result in substantial costs for societies. Future projections of such extreme occurrences are needed to successfully develop robust regional adaptation strategies. Model ensemble-based approaches provide a higher level of confidence since they compensate to some degree for the uncertainties of individual climate model projections. An ensemble of twelve regional climate projections from five regional climate models was used to evaluate the suitability of a modified version of the Rainfall Anomaly Index (mRAI) as an alternative to the Standardised Precipitation Index (SPI) in assessing future precipitation conditions. We compared frequency distributions and trends of the mRAI with the SPI for a test region that is climatologically representative of Central Eastern Europe. Both indices are highly correlated with each other at all tested timescales—both for stations and for regionally averaged data—with Pearson correlation coefficients >>0.9 and Spearman correlation coefficients >0.99. There are no significant differences in their frequency distributions, although the mRAI shows slightly higher frequencies in the classes of ‘moderately dry’ to ‘very dry’ conditions. The change signals revealed by SPI and mRAI are very similar for mean changes as well as for changes in the extremes. Considering the large bandwidth of change signals of individual regional climate projections, the mRAI provides sufficiently robust results for the evaluation of future precipitation anomaly trends. The notably more complex calculation of the SPI has no appreciable advantage for this application.

Quevauviller PP (ed) | Hydrometeorological hazards: interfacing science and policy

Hydrometeorological Hazards: Interfacing Science and Policy is the first book in the series Hydrometeorological Extreme Events that seeks to provide a multidisciplinary description of various scientific and policy features concerning hydrometeorological extreme events (Fig. 1). It is edited by Philippe P. Quevauviller (Vrije Universiteit Brussels), who is also the editor of this book series. The increased exposure and vulnerability of societies and the need to strengthen the knowledge base for related policies are highlighted by recent hydrometeorological extreme events. In this way, the book aims to present an overview of EU policies, of discussions on interfacing science and policy and of some fundamental knowledge on selected types of hydrometeorological events that will be further explored in the subsequent volumes of the series. The book is divided into four parts and a concluding chapter. These four main parts encompass 13 contributions of internationally renowned scientists and research groups. Altogether, 40 authors from 13 countries in Europe present the current scientific knowledge on the basic aspects of hydrometeorological hazards and related policies. The geographical scope of the contributions is mainly Europe, as most of the contributions introduce the results of a variety of European projects funded under the European Union’s Sixth Research Framework Programme (2002–2006) and the Seventh Framework Programme (2007–2013). References are given for each chapter and selected figures are—in

Chen D, Walther A, Moberg A, Jones P, Jacobeit J, Lister D | European trend atlas of extreme temperature and precipitation records

Climate change is most visible and dangerous to society when it comes to extremes. Hence an atlas that systematically illustrates the observed changes in temperature and precipitation extremes is strongly needed and desired. Thereby, the analysis of long-term time series is particularly attractive. This atlas advertises “an easy way to identify spatial patterns for a given time period, region, season, and index”. Unfortunately, the hopes and expectations raised by the title and abstract are abated by the content and structure of the book.

Climate science news in brief

Our News in Brief series is designed to offer different views revolving around the earth sciences, as various experts will be invited to provide a brief look around the recent research conducted in their area. The selection of research papers is left up to each expert and due to the broadness of each field is not intended to be a comprehensive overview. Links to the published work are provided in each section. In this issue we have invited Stephanie Hänsel, a postdoctoral senior researcher at the Interdisciplinary Environmental Research Center in Freiberg Germany, to select and summarize some of the latest findings in climate science. In this second article of our series, Hänsel gives a brief rundown on five research papers of global relevance.

Reviews on books, internet and scientific media

Modern Earth Sciences are unimaginable without models. Scientists build deterministic models for almost everything, but seldom explicitly address the connected uncertainty. Due to computational constraints, individual Earth models cannot be run for all possibilities or scenarios. In his book Modeling Uncertainty in the Earth Sciences, Jef Caers advocates to broaden the understanding of uncertainty and “build directly a model of uncertainty for practical decision purposes”. Thereby, he solely focuses on the Earth aspects of uncertainty.