At the moment there are 9 endorsed CORDEX Flagship Pilot Studies. The two latest additions for Africa and the TPE region were officially presented as endorsed at the ICRC-CORDEX 2019 in Beijing in October.
Africa: Modelling the Southeast African regional Climate
Southeastern Africa is a region with a population of ~270 million people who are strongly affected by the local climate. Hence, it is important to get a better understanding of the regional climate, how it has changed in the past, and how it is likely to change in the future. An important question is whether and how the rainfall over southeastern Africa responds to anthropogenic forcings as well as natural climate variability. Dominant atmospheric phenomena in this region include the intertropical convergence zone (ITCZ), the tropical monsoon and El Niño-Southern Oscillation (ENSO). Furthermore, it is important to revise and update climate knowledge based on local climate scientists. There is already scientific literature on climate change studies for southern Africa, but work remains in evaluating the model projections and calibrating their output with in-situ observations. Southeastern Africa is experiencing a climate change where trends in mean precipitation may be due to changes in the occurrence of rainy days or rain intensity. It is important to understand the causes of these trends. Likewise, it is important to understand how the local temperature responds to changing large-scale conditions. Such questions can be explored through downscaling the southeast African regional climate from global climate models (GCMs) experiments in CORDEX – Africa. The research will involve analysis of local observations, reanalysis, historical and data from regional climate models (RCMs) and empirical-statistical downscaling (ESD) to study dependencies between large-scale conditions and local variability in the rain and temperature statistics. ESD and RCM simulations will be combined to provide reliable future projections, for instance, by using RCMs as pseudo-reality and the statistical models to emulate seasonally aggregated high-resolution RCM output for a large ensemble of multi-model ensembles (CMIP). Local observations will also be used in the model evaluation to assess the added value of regional downscaling for both ESD and RCMs. The proposed Flagship Pilot Study (FPS) is tailored to investigate the connections between changes and trends, and special attention will be on the rainy season(s) and its/their duration. Identified dependencies will be utilised for making reliable future projections (ESD). The proposed study will also enable an investigation into the importance of regional scale forcings (aerosols, land-use change, vegetation etc) for the southeast African region. The results will be presented as aggregated statistics for daily temperature and precipitation together with assessments of the models.
Central Asia- East Asia: High resolution climate modelling with a focus on convection and associated precipitation
over the Third Pole region
Contact person: Deliang Chen firstname.lastname@example.org
The Third Pole (TP) is the Tibetan Plateau and all the mountain ranges that surround it. It has the world’s largest store of ice and snow outside the Arctic and Antarctic regions. The TP plays a significant role in the global climate system and is highly sensitive to humaninduced climate change. More than 10 major rivers originate from the TP, and the dramatic changes in the cryosphere have a great impact on water cycle, ecosystem and society over the TP and the surrounding regions. Due to the complex topography and harsh environment, ground-based observations are scarce over the TP, making the study of regional climate and its impact on other systems such as water and ecosystem difficult. Horizontal resolution of prevailing global reanalysis datasets is generally coarser than 30 km, which is not sufficient to examine convection and other mesoscale systems over the TP. High-resolution regional downscaling is badly needed for understanding processes and improve projections. This project aims at enhancing our understanding of the regional characteristics of water cycle changes over the TP region with a special focus on the convection and precipitation. The spatial scale of annual precipitation is generally small. Convection system contributes significantly to the total precipitation over the TP, and is therefore a key to understand the water cycle of the region. Thus, we will investigate the impact of convection system on the water cycle, especially precipitation. The contribution of Mesoscale Convective Systems (MCSs) to the precipitation over the TP will be addressed by using the Rain Cell Tracking method. A multi-model and/or multischeme approach will be utilized to assess the ability of regional climate model (RCM) in simulating convective precipitation over the TP, with the aid of satellite observations and water isotope observations. The targeted resolution is 2-9 km with a focus on convectionpermitting simulations (2-4 km). The simulations from different models or model configurations will be intercompared. We will start with a test simulation of one year. When this is done successfully, we plan to run a subset of models/model setups for a multi-year period between 1979 and 2018. The exact number of years will depend on the evaluation of the one year test and the computing resources available. The outcomes of the project are expected to enhance our understanding of processes relevant for cloud and precipitation formation, convection, MCS, and local wind system. They should also be useful to future high resolution regional climate modeling and regional reanalysis over the TP. Other studies, such as the water cycle will also benefit from the results of this project. An international was established for this project, including experts in regional climate modeling, relevant observation, statistical analysis, water isotope modeling and observations, as well as regional cryosphere and climate studies. Most of the teams have been actively engaged in or are in leading positions for an international research program the Third Pole Environment (TPE) which calls for such an effort. This project has a great potential to be successful and useful to WCRP in general and CORDEX in particular.
Africa: ELVIC – Climate Extremes in the Lake Victoria Basin
Contact person: Nicole van Lipzig email@example.com
Extreme weather events, like heavy precipitation, heat waves, droughts and wind storms have a detrimental impact on East African societies. The Lake Victoria Basin (LVB) is especially vulnerable: It is estimated that each year 3,000-5,000 fishermen perish on the lake due to nightly storms (Red Cross,
2014). In addition, the LVB is a global hotspot of future population growth and urbanization. Urban dwellers in this region with low infrastructure are particularly vulnerable to climate extremes, such as urban flooding. As the frequency and intensity of climate extremes is projected to further increase substantially with climate change, so do the risks, with potentially major consequences for livelihoods of peoplein the LVB.
Future climate projections for the LVB are challenged by thecomplexity of the region. The mesoscale circulation induced by the lake and by the complex orography surrounding the basin, strongly modulate the climate change signal. Moreover, current state-of-the-art climate simulations over the region parameterise convection, while Convection Permitting Models (CPMs) have shown a strong added value in representing convection in other regions of the world. Altogether this urges for reducing model resolution to grid sizes of less than 5 km.
The computational cost of CPM integrations is currently so high that individual groups can only afford one realization of a possible future climate. Ensemble climate projections at the CPM scale are only possible in internationally coordinated programmes such as CORDEX. We therefore propose the CORDEX Flagship Pilot Study (FPS) “ELVIC – climate Extremes in the Lake VICtoria basin” with the overall objective to provide robust climate information on extremes to the impact
community. Thereby, ELVIC answers the following questions:
- Are moist convective systems in Equatorial Africa better
represented by CPMs compared to models that rely on a
parametrization of convection?
- How can we best combine information of CMIP and
CORDEX-Africa with CPM (climate change) integrations?
- How will extreme weather events evolve in the future in
- How can improved probabilistic information on convective
extremes be used by the impact community?
An assessment of the capability of CPMs to represent extremes is only possible when sufficient observational data are available. With the recently endorsed Hydroclimate project for Lake Victoria (HyVic) and the UK-led project HyCRISTAL (Integrating Hydro-Climate Science into Policy Decisions for Climate-Resilient Infrastructure and Livelihoods in East Africa), observations are planned in the region. This, together with the emergence of a group of scientists planning or already
performing CPM integrations in the region makes ELVIC extremely timely. This FPS is an effort to coordinate activities between these groups.
With this FPS we want to improve climate change adaptation
strategies in the LVB by providing useful climate information
The presentation from the ICRC-CORDEX2019 can be found here
Africa: Coupled regional modelling of land-atmosphere-ocean interactions over western-southern Africa under climate change
Contact person: Francois Engelbrecht firstname.lastname@example.org
The climate system of western-southern Africa is highly coupled and exhibits intricate interactions between the land, atmosphere and ocean. The dominating biome is the African savannahs, where complex tree-grass interactions are shaped by fire and land-use.
It has been postulated that under future climate change rising CO2 levels and increasing temperatures may favor trees over grasses in the savannah, leading to bush encroachment at the expense of biodiversity and grazing potential. However, given that that much of southern Africa is likely to become drier and significantly warmer under climate change (a conclusion of the Africa Chapter of AR5) it is plausible that mega-fire events may occur more frequently in savannahs, effectively favoring grasses over trees.