Dr Christian WolffSenior Research Associate - Tropical Palaeoclimatology
My research aims to contribute to a better understanding of the mechanisms driving the global climate system by building high resolution climate records to assess regional (a)synchronicity of environmental responses to climate forcing. To date, much of my research is focusing on the tropical region using climate archives like lake sediments (e.g. Kenya, Tanzania, Hawaii, Vanuatu, India) and speleothems (Kyrgyzstan) to reconstruct past seasonal dynamics. Main goal of all research topics are the examination of frequency and magnitude of extreme events (ENSO, floods, droughts, storms) over time, and their relationships to forcing, which are of particular relevance to societal concerns.
Interannual rainfall variations in equatorial East Africa are tightly linked to the El Niño Southern Oscillation (ENSO), with more rain and flooding during El Niño and droughts in La Niña years, both having severe impacts on human habitation and food security. Located on the eastern flank of Mount Kilimanjaro, Lake Challa, a freshwater crater lake is a unique archive to study interannual rainfall variability during the past 250.000 years on annually laminated sediments. ICDP DeepCHALLA
The impact of global warming on current and future water resources is attracting increasing attention. Virtually no other region on Earth is thought to be affected as strongly by future changes in water supply than arid Central Asia. Different climate archives have been used for understanding the history and mechanisms of climate related rainfall pattern in Central Asia during the Holocene especially in the analyses of long-term changes in zonal and meridonal atmospheric circulation patterns and its teleconnections, such as the North Atlantic Oscillation (NAO). Speleothems from Uluu-Too cave located in the core region of arid Central Asia between the foothills of the Tien Shan and the intramontane Fergana Valley in south-western Kyrgyzstan will help to understand hydrological changes in the Central Asian mountains and to unravel the forcing mechanisms behind precipitation variations.
Oxygen and Carbon isotopic composition from a speleothem from the southern rim of the Fergana Basin in Kyrgyzstan (Keklik-Too) allows the examination of winter/spring precipitation in this area and the corresponding link with the NAO. One of the aim of the project is to get further information how the strength of Westerlies system is linked to Atlantic Sea Surface temperature and the effects on global circulation pattern (Siberian High and Asian Monsoon dynamics).
The Hawaiian Islands are a world-renowned vacation spot, famous for their beautiful islands lined with beaches of warm, white sand and verdant, lush flora. However, these islands of paradise in the centre of the Pacific are vulnerable to the impacts of global warming. Sediments from the bottom of Ordy Pond, a small sinkhole on the Oahu Island, Hawaii will help to reconstruct rainfall pattern and vegetation response during the past 10,000 years by using Oxygen and carbon isotopes (δ18O; δ13C). Our data will also help to give new insights into the climate at the time of the first human settlement of the main Hawaiian Islands by the Polynesians 1200 years ago and their impact to the Island.
e.g.: coming soon
East African vegation response to a predicted intensified ENSO
The El Niño Southern Oscillation (ENSO), is the main driver for the interannual variability inEast African rainfall with significant impact on vegetation and agriculture, and dire consequences in food and social security. In this project, we identify and quantify the ENSO contribution to the East African rainfall variability to forecast future East African vegetation response to rainfall variability related to a predicted intensified ENSO.