Raquel V. Francisco

Regional Climate Modeling for the Developing World: The ICTP RegCM3 and RegCNET

Regional climate models are important research tools available to scientists around the world, including in economically developing nations (EDNs). The Earth Systems Physics (ESP) group of the Abdus Salam International Centre for Theoretical Physics (ICTP) maintains and distributes a state-of-the-science regional climate model called the ICTP Regional Climate Model version 3 (RegCM3), which is currently being used by a large research community for a diverse range of climate-related studies. The RegCM3 is the central, but not only, tool of the ICTP-maintained Regional Climate Research Network (RegCNET) aimed at creating south–south and north–south scientific interactions on the topic of climate and associated impacts research and modeling. In this paper, RegCNET, RegCM3, and illustrative results from RegCM3 benchmark simulations applied over south Asia, Africa, and South America are presented. It is shown that RegCM3 performs reasonably well over these regions and is therefore useful for climate studies in...

Evaluating uncertainties in the prediction of regional climate change

Uncertainties in regional climate change simulations for the 21st century by five coupled atmosphere-ocean General Circulation Models (AOGCMs) (two of them including ensembles of simulations), for different anthropogenic forcing scenarios and 23 regions in the World, are examined. Seasonally and regionally averaged precipitation and surface air temperature for the future period of [2070–2099] as compared to the period of [1961–1990] are considered. The dominant source of uncertainty in the simulation of average regional climate change is due to inter-model variability with inter-scenario and internal model variability playing secondary roles. The range of predicted climate changes by different realizations of the same ensemble is small, and simulated changes exhibit a high level of coherency among different forcing scenarios. Uncertainties in regional changes are 3 K or greater for temperature and 25% of present day values or greater for precipitation. The model biases in reproducing present day climate are ≤1 K to over 5 K for temperature and ≤10% to over 100% for precipitation.

Uncertainties in regional climate change prediction: a regional analysis of ensemble simulations with the HADCM2 coupled AOGCM

Abstract We analyze ensembles (four realizations) of historical and future climate transient experiments carried out with the coupled atmosphere-ocean general circulation model (AOGCM) of the Hadley Centre for Climate Prediction and Research, version HADCM2, with four scenarios of greenhouse gas (GHG) and sulfate forcing. The analysis focuses on the regional scale, and in particular on 21 regions covering all land areas in the World (except Antarctica). We examine seasonally averaged surface air temperature and precipitation for the historical period of 1961–1990 and the future climate period of 2046–2075. Compared to previous AOGCM simulations, the HADCM2 model shows a good performance in reproducing observed regional averages of summer and winter temperature and precipitation. The model, however, does not reproduce well observed interannual variability. We find that the uncertainty in regional climate change predictions associated with the spread of different realizations in an ensemble (i.e. the uncertainty related to the internal model variability) is relatively low for all scenarios and regions. In particular, this uncertainty is lower than the uncertainty due to inter-scenario variability and (by comparison with previous regional analyses of AOGCMs) with inter-model variability. The climate biases and sensitivities found for different realizations of the same ensemble were similar to the corresponding ensemble averages and the averages associated with individual realizations of the same ensemble did not differ from each other at the 5% confidence level in the vast majority of cases. These results indicate that a relatively small number of realizations (3 or 4) is sufficient to characterize an AOGCM transient climate change prediction at the regional scale.

Emerging patterns of simulated regional climatic changes for the 21st century due to anthropogenic forcings

We analyse temperature and precipitation changes for the late decades of the 21st century (with respect to present day conditions) over 23 land regions of the world from 18 recent transient climate change experiments with coupled atmosphere-ocean General Circulation Models (AOGCMs). The analysis involves two different forcing scenarios and nine models, and it focuses on model agreement in the simulated regional changes for the summer and winter seasons. While to date very few conclusions have been presented on regional climatic changes, mostly limited to some broad latitudinal bands, our analysis shows that a number of consistent patterns of regional change across models and scenarios are now emerging. For temperature, in addition to maximum winter warming in northern high latitudes, warming much greater than the global average is found over Central Asia, Tibet and the Mediterranean region in summer. Consistent warming lower than the global average is found in some seasons over Southern South America, Southeast Asia and South Asia, while cases of inconsistent warming amplification compared to the global average occur mostly in some tropical and southern sub-tropical regions. Consistent increase in winter precipitation is found in northern high latitude regions, as well as Central Asia, Tibet, Western and Eastern North America, and Western and Eastern Africa regions. The experiments also indicate an increase in South Asia and East Asia summer monsoon precipitation. A number of regions show a consistent decrease in precipitation, such as Southern Africa and Australia in winter, the Mediterranean region in summer and Central America in both seasons. Possible physical mechanisms that lead to the simulated changes are discussed.

Effects of a Subgrid-Scale Topography and Land Use Scheme on the Simulation of Surface Climate and Hydrology. Part I: Effects of Temperature and Water Vapor Disaggregation

Abstract A mosaic-type parameterization of subgrid-scale topography and land use is implemented within the framework of a regional climate model, and its effects on a multiseasonal simulation over the European region are tested, with focus on the Alpine subregion. The parameterization adopts a regular finescale surface subgrid for each coarse model grid cell. Meteorological variables are disaggregated from the coarse grid to the fine grid, land surface calculations are then performed separately for each subgrid cell, and surface fluxes are reaggregated onto the coarse grid cell for input to the atmospheric model. The primary effects of the subgrid surface scheme are 1) an improvement of the finescale structure and overall simulation of surface air temperature over complex terrain, and 2) a more realistic simulation of snow as driven by the complex terrain features. The subgrid scheme also affects the warm season simulation through feedbacks between precipitation and the surface hydrology. The primary aspe...

A study on impact of climate variability/change on water resources in the Philippines

Abstract An effort to investigate possible effects of climate variability/change on water resources in the Philippines has been undertaken. Long term temperature and rainfall trends at various stations as well as hydrologic parameters in multipurpose dams in the Philippines were examined. Results indicated generally increasing trends of yearly temperature at representative stations. However, the inter-annual variations of yearly and seasonal rainfall indicated geographical patterns among trends. Rainfall trends in western Luzon are mainly increasing while decreasing trends are indicated in eastern section of Luzon, most parts of Visayas and the whole of Mindanao. Water inflows in the major multipurpose dams in Luzon and at Lake Lanao in Mindanao indicated decreasing trends. Decrease of water inflow is found to be prominent during ENSO events. Most drought occurrences based on climatological studies in the Philippines are found to be ENSO-related. At this stage of the investigation, there is a tendency to believe that the trends exhibited by the above-mentioned parameters are associated with some shifting in the global circulation patterns. Effects of other factors such as land use change, increase of population and other non-climatic factors on such trends can not however be discounted.

Uncertainties in the Prediction of Regional Climate Change

Uncertainties in regional climate change predictions for the 21st century by five coupled atmosphere-ocean General Circulation Models (AOGCMs) (two of them including ensembles of simulations), for different anthropogenic forcing scenarios and 23 regions in the World, are examined. The variables considered are seasonally and regionally averaged precipitation and surface air temperature for the future period of [2071–2100] as compared to the present day period of [1961–1990]. We find that the dominant source of uncertainty in the simulation of regional climatic changes by AOGCMs is due to inter-model variability with inter-scenario and internal model variability playing secondary roles. For both models including ensemble simulations, the spread of predicted average climatic changes by different realizations of the same ensemble is small. In addition, simulated regional climatic changes exhibit a high level of coherency among different forcing scenarios. Overall, uncertainties in predicted regional changes by the five AOGCMs are of the order of 3 K or greater for surface air temperature and 25% of present day values or greater for precipitation. These uncertainties would be transmitted to any regionalization technique used to enhance the regional information of AOGCMs. Differences between AOGCMs and their effects on the model simulations need to be better understood in order to increase confidence in the prediction of regional climate change due to anthropogenic forcings.

Greenhouse Gas Inventory of the Philippines: Interim Report

This paper presents the latest update on the greenhouse gas inventory for the Philippines, with 1990 as the base year. The carbon dioxide sources covered in the inventory are fossil fuel burning, cement production, and land-use change and forestry. The net emission of carbon dioxide totaled 128,620 Gg CO2, of which land-use change and forestry accounted for 68%. The carbon dioxide emissions from biomass burning and bunker fuel consumption were not included in the total emission. The national methane emission of 1,026 Gg CH4 was estimated from biomass burning, coal mining and oil activities, rice cultivation, livestock production, and forestry and land-use change activities. Paddy rice cultivation, which is the largest source, accounted for 36% of the total. The emission factor used, which is one-fourth of the default value recommended by the IPCC, was based on a preliminary study made by the Philippine Rice Research Institute, in collaboration with the International Rice Research Institute.