IME: Coping with Uncertainty: Concept of Robust Solutions

Tatiana Ermolieva (IME/LUC) presented what will probably be one of the most useful lectures of the YSSP for my research. Uncertainty is inherent in every decision one takes, how do you design a system that copes with it?

There are two types of systems (processes), one is the traditional natural system like physics that is governed by fixed relations, the other is human-related systems governed by old and new policies dependent on decisions of various agents/actors. From this we can distinguish knowable and unknowable (inherent: natural systems) uncertainties.

Human-related systems require a new approaches to stability (security) analysis. There are multiple reasons, the lack of observations, the expense of experimentation, observations contaminated by old policies and observations of results/impacts may come with a delay or cause irreversible change (climate change for instance)

Although its impossible to predict human-driven systems, it is possible to find robust solutions good against all uncertainties. These robust policies assist in the long-term stability of systems performance.

Popular security analysis includes aggregate analysis, least-squares analysis etc but these are not robust solutions, all are sensitive to outliers. I've appropriated the image above because it is one of the best examples I've ever seen of a mean/median/mode argument. The mean is in red, the median in green and the mode in maroon. Notice how most of the information is lost in the case of the mean. Remember: the mean is MEANINGLES! The median is more robust.
A common feature of most systems is a range of possible outcomes resulting from different scenarios or the variability (eg weather). The uncertainty is which scenario comes next?

I'm currently making my way through 'Coping with Uncertainty: Robust Solutions'. Its written by the IME group at IIASA and works through various techniques for robust systems mostly through real-world applications. The UCT library is in the process of buying a copy, it should arrive sometime in the next year :P

Science on Global Problems Area: Food & Water

IIASA has defined three new strategic research areas: Food & Water, Energy & Climate Change and Poverty & Equity.

Food & Water has been shared by a few groups within IIASA's research groups; Forestry, Ecology and Land Use Change. They reviewed current research activities and highlighted a few key challenges in this global problem area. These include:

• Widespread hunger and rising global food demands
• Agriculture needs to increase 70% globally and 100% in the developing world
• Agriculture currently uses 70% of all anthropogenic water use.
• Fishing currently feeds 1 billion people but won't be sustainable with the current overfishing
• A need for robust expansion of food and bioenergy production with sustainable regulating ecosystem functions protecting the global gene pool.
• Strategies for copying with climate change needs to be location specific.

Each group expounded on possible research avenues. Its quite fascinating what some of the proposed solutions entail. One worrying fact is that the capacity for rain-fed agriculture in Africa is decreasing by 2050, which given that 95% of the crop-land in Africa is rain-fed and contributes 35% to the GDP and 70% of the employment and 40% of the exports (according to FAO in 2000), maybe that should be a major focus on the African agenda.

Journal Club MTG9: Land Use and Land Cover Change

My topic of research while in Michigan is on Land Use and Land Cover Change which made today's paper which I had to present especially interesting. The paper "Evaluating the effects of historical land cover change on summertime weather and climate in New Jersey: Land cover and surface energy budget changes" by Paul Wichansky et al (2008), investigates the sensitivity of a warm season climate of New Jersey to land cover change from 1880s versus 1990s. The areas of specific interest include the magnitude of land cover change and sensitivity on near surface air temperature, rainfall, dew point temperature, heat fluxes and climatological episodes.

Previous studies have shown that deforestation causes an increase in temperature and rainfall shifts, while reforestation causes cooling in the region. Urbanisation also causes an increase in temperatures and changes to the diurnal cycle. The interesting thing to note is that all three processes have occurred in the state of New Jersey within the last century. Reconstructing the land cover from historical topographical maps and land consensus, a full land cover map was available for direct comparison with NLCD data from 1992. Aggregated to 1km and combined into 8 vegetation classes, the researchers used RAMS and LEAF2 to compare atmospheric responses to land cover change.

They nested the grid in 3 levels (above-purple) and 3 ensemble members per land cover scenario, they used a 2 month period in June/July 1999. From NCEP data to force atmospheric boundary conditions, they used June as a spinup and July as a month for analysis. The soil moisture was described from observation.

The model comparisons showed an increase in near surface air temperature and dew point temperature in urban and deforested areas and cooler in reforested areas, just as previous research stated. The results overall come as no surprise but they way they use the ensemble without giving the spread or error is slightly weird.

Met Office

I boarded a train at 8.30 this morning for Exeter. What's in Exeter? The Met Office. The SAWS equivalent with more money. We got a taxi to the office, nice change to walking and trying to catch buses. The taxis wasn't allowed into the grounds until he identified the passengers. The Met Office is very tight with security. We were escorted to the bathroom!

The visit itself was mind-boggling. The place is huge. Has its own gym and cafeteria. Bruce gave a talk about ICA and stakeholder needs. Between all this I met a variety of researchers, all of which explained their research. I now have a massive task of trying to remember the content and go back to look it up when I have more time. Amongst this is: Land use change, snowpacks, perturbed physics, downscaling, ICA, DFID, fires in RCM, albedo from burning, vegetation feedbacks, splines, SOMs hierachies.