Separation of anthropogenically/solar forced from internal climate variability
An actual problem of increased scientific and socio-politic interest is related to the causes of the observed 20th century warming trend of global average surface temperature. At least three types of causes may be responsible for this trend:
· the anthropogenic forcing related to increased emissions of greenhouse gases in the atmosphere during the modern period, due to human activity
· increased solar irradiance
· internal interactions between the components of the climate system.
My work in this area is related to the qualitative and quantitative distinction between the contributions of these types of forcings to climate changes.
Climate modes of interannual to millennial timescales
One of the general feature resulting from statistical analyses of observational data is the emergence of what are called 'modes' of climate variability, characterized by coherent spatial variability at quasi-global scale and, in some cases, by quasi-periodic evolution. Part of my work is related to the description and understanding of the physical mechanisms associated to some prominent climate modes, like:
· El Nino Southern Oscillation: involves interannual variations in the tropical Pacific
· Atlantic Multidecadal Oscillation: involves changes in the thermohaline circulation
· Dansgaard-Oeschger events: most prominent abrupt climate changes in the last 120,000 year
· 100,000 year cycle: marks the glacial/interglacial transitions in the last million years.
Using proxy records to reconstruct and understand
For a non-specialist, the possibility to reconstruct the past climate for the pre-instrumental period (before the last 150 years) may appear as a surprise. Presently, proxy data are obtained from corals, tree rings, sediments, ice-cores, fossil pollen, speleothems and historical data. Although there is a huge potential for past climate reconstructions based on proxies, it is not a trivial task to identify and understand the relevant information that proxy data contain. I am using proxy data to infer the physical mechanisms of the climate modes.
This is an exotic and interesting topic for me. I find such interdisciplinary approaches as very good opportunities to expand the view and to learn new things. Also, is my conviction that apparently strange and interesting comparison and analogies between concepts in two very different fields may lead to important progress in either of the two domains. I became interesting in this topic due to a personal hypothesis, that climate may have a stronger impact on the socio-economic activity than is generally expected. However, the limited time available allows me only sporadic efforts related to this topic.