Frank Kaspar

A model‐data comparison of European temperatures in the Eemian interglacial

Compared to the wide range of different models used for the analysis of the climate system, GCMs have the most complex representation of the atmospheric physical processes. We have chosen the ECHO-G model as a state-ofthe-art OA-GCM to simulate the climatic conditions at 125 kyr BP by adapting the orbital parameters and greenhouse gas concentrations. [4] For terrestrial palaeoclimate reconstructions, the use of botanical fossils is well-established, because vegetation is in close relation to climate. Mainly pollen can be found in large numbers in suitable sediments, and macro remains add valuable information for important climate indicator species. For the reconstructions, recently developed botanical � � � � � � � � � � � � � � � � � � � � � ��

Simulation of East African precipitation patterns with the regional climate model CLM

Climate simulations for East Africa have been performed with the regional climate model CLM. Here we evaluate the quality of simulated precipitation by comparing it with observations. Different schemes for convection and cloud ice have been tested in order to determine the configuration with best representation of precipitation patterns for the region. The simulated seasonal behaviour of precipitation is reasonable in all configurations, whereas absolute values are strongly influenced by the selected schemes. Best agreement with observations is achieved with the Tiedtke mass-flux convection scheme in combination with a two-category cloud ice scheme, that considers cloud ice as an additional solid form of water. With the Kain-Fritsch convection scheme the model generally overestimates precipitation. Regional differences are discussed.

Simulations of the Eemian interglacial and the subsequent glacial interception with a coupled ocean-atmosphere general circulation model

Abstract A coupled ocean-atmosphere general circulation model was used to perform multicentennial climate simulations of the Eemian interglacial and the subsequent glacial inception. The simulations are performed as equilibrium experiments with orbital parameters and greenhouse gas concentrations set to values of 125000 and 115000 years before present (BP). These dates represent periods with enhanced and weakened seasonal cycles of insolation on the northern hemisphere. Significant changes in seasonal temperatures are simulated in particular for the continental areas of the northern hemisphere. Comparisons with pollen-based reconstructions of European temperatures show that the model simulates realistic spatial temperature patterns for the warm phase of the Eemian. For 115 000 years BP, the reduction in summer insolation leads to a perennial snow coverage over parts of North America, which is continuously expanding. Together with a continuous increase of Arctic sea ice volume, this results in a long-term cooling trend. Consistent with geological records, the snow accumulation starts in north-eastern Canada. In this region, southward winds transport cold Arctic air onto the continent.

Simulated Relationships between Regional Temperatures and Large-Scale Circulation: 125 kyr BP (Eemian) and the Preindustrial Period

To investigate relationships between large-scale circulation and regional-scale temperatures during the last (Eemian) interglacial, a simulation with a general circulation model (GCM) under orbital forcing conditions of 125 kyr BP is compared with a simulation forced with the Late Holocene preindustrial conditions. Consistent with previous GCM simulations for the Eemian, higher northern summer 2-m temperatures are found, which are directly related to the different insolation. Differences in the mean circulation are evident such as, for instance, stronger northern winter westerlies toward Europe, which are associated with warmer temperatures in central and northeastern Europe in the Eemian simulation, while the circulation variability, analyzed by means of a principal component analysis of the sea level pressure (SLP) field, is very similar in both periods. As a consequence of the differences in the mean circulation the simulated Arctic Oscillation (AO) temperature signal in the northern winter, on interannual-to-multidecadal time scales, is weaker during the Eemian than today over large parts of the Northern Hemisphere. Correlations between the AO index and the central European temperature (CET) decrease by about 0.2. The winter and spring SLP anomalies over the North Atlantic/European domain that are most strongly linearly linked to the CET cover a smaller area and are shifted westward over the North Atlantic during the Eemian. However, the strength of the connection between CET and these SLP anomalies is similar in both simulations. The simulated differences in the AO temperature signal and in the SLP anomaly, which is linearly linked to the CET, suggest that during the Eemian the link between the large-scale circulation and temperaturesensitive proxy data from Europe may differ from present-day conditions and that this difference should be taken into account when inferring large-scale climate from temperature-sensitive proxy data.

MiKlip - a National Research Project on Decadal Climate Prediction

AbstractMittelfristige Klimaprognose (MiKlip), an 8-yr German national research project on decadal climate prediction, is organized around a global prediction system comprising the Max Planck Institute Earth System Model (MPI-ESM) together with an initialization procedure and a model evaluation system. This paper summarizes the lessons learned from MiKlip so far; some are purely scientific, others concern strategies and structures of research that target future operational use.Three prediction system generations have been constructed, characterized by alternative initialization strategies; the later generations show a marked improvement in hindcast skill for surface temperature. Hindcast skill is also identified for multiyear-mean European summer surface temperatures, extratropical cyclone tracks, the quasi-biennial oscillation, and ocean carbon uptake, among others. Regionalization maintains or slightly enhances the skill in European surface temperature inherited from the global model and also displays h...

Insolation during interglacials

Abstract The main insolation parameters are reviewed, in particular the energy received by the whole Earth over a full year and the 24-hour mean irradiance. Their spectral characteristics are underlined, and some remarks are made about the differences between insolation at the top of the atmosphere and at the Earths surface, the caloric and the astronomical seasons, the insolations in the tropical and in the high latitudes, the mid-month and the calendar insolations. The insolations characterizing interglacials marine isotope stage (MIS) 1 to MIS 11 are described, and their common features are discussed.

Worldwide survey of awareness and needs concerning reanalyses, and respondents views on climate services

AbstractA worldwide online survey about user awareness of reanalyses and climate services was conducted in the period from November 2013 to February 2014 by the Coordinating Earth Observation Data Validation for Re-Analysis for Climate Services (CORE-CLIMAX) project. The 2,578 respondents were mostly users of global reanalyses [particularly the European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), National Aeronautics and Space Administration (NASA), and Japan Meteorological Agency (JMA) reanalyses]. They answered queries arranged in 11 sections by choosing from preprepared check-box responses and left several hundred free comments. Here, we analyze responses related to characteristics of reanalysis data and the perceived obstacles for using reanalysis in climate services. After examining responses from all survey participants, we focus on the answers from subgroups working in specific disciplines related to natural resource management: freshwate...

Pan European Phenological database (PEP725): a single point of access for European data

The Pan European Phenology (PEP) project is a European infrastructure to promote and facilitate phenological research, education, and environmental monitoring. The main objective is to maintain and develop a Pan European Phenological database (PEP725) with an open, unrestricted data access for science and education. PEP725 is the successor of the database developed through the COST action 725 “Establishing a European phenological data platform for climatological applications” working as a single access point for European-wide plant phenological data. So far, 32 European meteorological services and project partners from across Europe have joined and supplied data collected by volunteers from 1868 to the present for the PEP725 database. Most of the partners actively provide data on a regular basis. The database presently holds almost 12 million records, about 46 growing stages and 265 plant species (including cultivars), and can be accessed via http://www.pep725.eu/. Users of the PEP725 database have studied a diversity of topics ranging from climate change impact, plant physiological question, phenological modeling, and remote sensing of vegetation to ecosystem productivity.

What’s on the 5th IPCC Report for West Africa?

The status of knowledge on observed and projected climate change is regularly summarized in the assessment reports of the Intergovernmental Panel on Climate Change. The latest IPCC report (2013) concludes that Africa as a whole is one of the most vulnerable continents due to its high exposure and low adaptive capacity. Here, the major conclusions of the report for Western Africa are summarized. Although there are still large gaps in the available data, evidence of warming over land regions across Africa, consistent with anthropogenic climate change, has increased. Temperature projections over West Africa for the end of the 21st century from global climate simulation range between 3 and 6 °C above the late 20th century baseline depending on the emission scenario. A similar range is produced with regional climate models that are used to downscale global climate simulations. For some regions, unprecedented climates are projected to occur at around 2040. Important progress has been made in the understanding of West African weather systems during the African Monsoon Multidisciplinary Analysis (AMMA; phase 1: 2002–2010, phase 2: 2010–2020) project. For many processes in ecology, agriculture or hydrology, precipitation is one of the most important parameters. In addition to the total precipitation, the onset of the rainy season is of special interest for agriculture. In the past a shift of the rainy season was discussed, but currently a shift cannot be observed for West Africa. However, the length of the Sahelian rainy season reveals an increasing trend of 2–3 days per decade, with a drier phase within. Since the 1950s annual precipitation has tended to decrease in western and eastern parts of the Sahel region, with a very dry period in the 70s and 80s and a slight increase of precipitation afterwards, until today. However, climate projections show a slight increase of total precipitation and a longer rainy season with a drier phase within.

Beobachtung von Klima und Klimawandel in Mitteleuropa und Deutschland

Wetterdienste und andere Forschungseinrichtungen in Deutschland und seinen Nachbarlandern beobachten seit dem 19. Jahrhundert, wie sich das Klima in Mitteleuropa verandert. Auf Basis der gesammelten Beobachtungen lassen sich Aussagen uber die Klimaentwicklung in Deutschland treffen: Die Daten erlauben Beschreibungen der Atmosphare vom taglichen Wetter bis zu mehreren Jahrzehnten, uber die sich das Klima andert. Daruber hinaus liefern die Langzeitbeobachtungen auch Datensatze, welche die Uberprufung von Klimamodellen ermoglichen. Das Kapitel stellt schwerpunktmasig die Geschichte der Beobachtungen sowie die tatsachlich gemessene Veranderung verschiedener Klimakenngrosen fur Deutschland dar. Auserdem werden Nutzbarkeit und Einschrankungen der Datensatze fur die Evaluation der Klimamodelle bewertet.