Dr Niels Crosley Munksgaard

PhD (Copenhagen University 1986), Senior Research Fellow CDU and JCU.

Stable isotopes in precipitation and paleoclimatic archives in tropical areas to improve regional hydrological and climatic impact models

An International Atomic Energy Agency Cooperative Research Program (IAEA-CRP)

The impacts of climate change on freshwater systems are mainly due to the observed and projected increases in temperature, sea level and precipitation variability. Incorporating stable isotope physics in General Circulation Models (GCM) provides a promising means to study the mechanisms causing isotopic variability in precipitation, including the processes that cause isotopic variability in paleoclimatic archives such as speleothems.

To understand the mechanisms that control these changes in precipitation isotopes would enhance our ability to use isotope data to improve the predictive capabilities of climate models as well as interpretation of past climate archives. This will in turn contribute to a better understanding of impacts of climate change on variability, availability and sustainability of fresh water resources.

While isotope-equipped atmospheric GCMs reproduce reasonably well the global distribution of mean annual isotope contents of modern precipitation, they fail to explain observed shorter-term variations on regional and local scales in tropical areas.

Tropical regions have remained challenging in terms of understanding variations in precipitation isotopes. This is partly due to poor spatial and temporal data coverage of tropical regions. During 2013-17 the IAEA CRP has systematically been collecting and analysing precipitation at high frequency from over 70 stations in the tropics and has helped improve our understanding of the mechanisms that govern precipitation isotope composition.

At JCU Niels develops and applies new portable instruments for field-based analysis of stable isotopes (H, C, O) in water, soil and other environmental samples. This work includes building some novel instruments (gadgets) that help provide new insights into weighty questions about global water and carbon cycling.