FUTURE CARIBBEAN CLIMATES FROM STATISTICAL AND DYNAMICAL DOWNSCALING Arnoldo Bezanilla Morlot Center For Atmospheric Physics Institute of Meteorology, Cuba The Caribbean Community Climate Change Centre
OUTLINE OF PRESENTATION Downscaling Techniques How well Downscaling simulations represent present Climate Trends present Climate Trends future Climate Conclusions Final Thougts
Downscaling Techniques Downscaling relies on the assumption that local climate is a combination of large-scale climatic/atmospheric features (global, hemispheric, continental, regional) and local conditions (topography, water bodies, land surface properties). Representation of the latter is generally beyond the capacity of current GCMs. Deriving climate projections at local scales is a multistep process. At each step, assumptions and approximations are made. Uncertainties are inherent in projections of changes in climate and their impacts. They arise from different sources and need to be kept in mind, whether explicitly quantified or not Downscaling can be applied spatially and temporally. Oftentimes, several downscaling methods are combined to obtain climate change information at desired spatial and temporal scales. There are two principal ways to combine the information on local conditions with large-scale climate projections: Dynamical and Statistical
Downscaling Techniques WHICH DOWNSCALING TECHNIQUE IS MOST APPROPRIATE YOUR STUDY?
Downscaling Techniques
Downscaling Techniques
How well Downscaling simulations represent present Climate? Centella et al, 2014 Size of the domain Vs the quality of the simulations
How well Downscaling simulations represent present Climate? Different Cloud Microphysics Schemes and Cumulus parameterizations Martinez et al. 2017
How well Downscaling simulations represent present Climate? Drought processes HERRERA AND AULT 2017
How well Downscaling simulations represent present Climate? Fuentes et al 2013 Number of tropical cyclone days (NCD) for the 1982 2008 period. a) Observed from HURDAT b) From RegCM4 simulation
Trends Present Climate T. S. STEPHENSON et al. 2014 Temperatures are increasing
Trends Present Climate Warm days Temperatures are increasing A rising trend in mean temperature ~ 0.1 oc/decade. Warm days have steadily increased (~22 days since 1960) Warm nights have steadily increased (~21 days since 1960) Cold nights and days have decreased (~14 fewer cold nights since 1960) T. S. STEPHENSON et al. 2014 Warm nights Cool nights
Trends Present Climate North Caribbean Rainfall more variable West Caribbean East Caribbean South Caribbean Jones et al (2015 submitted)
Trends Present Climate T. S. STEPHENSON et al. 2014 Total rainfall Intense rainfall Trends in the intensity, frequency and duration of rainfall events i.e. a noticeable shift in the character of regional rainfall. Whereas an overall drying or wetter trend is not evident, the number of dry days between rain events is increasing, and when rain occurs it tends to be heavier.
Trends Present Climate Sea levels are rising Caribbean s rate of sea level rise appears to follow the global mean.
Trends Future Climate Temperatures increasing Mean changes in the annual mean surface temperature for 2071-2099 with respect to 1961-1989, as simulated by regional climate models. th International Climate Change Conference in the Caribbean, October 9-12th, 2017
Trends Future Climate(Temperatures still increasing) 2010 2040 2041 2070 Irrespective of scenario the Caribbean expected to warm. Warming between 1 and 3.5oC Warming consistent with projections for other parts of globe. Warming far exceeds historical variability
Cool Nights Warm Days Mean Temps Trends Future Climate Temperatures still increasing 30-98% of days annually will be considered hot by the 2090s Only 2% cool by the 2080s By mid 2020s-2030 every year (in the mean) will be warmer than hottest year felt to date. CLIMATE DEPARTURE
Trends Future Climate Drying trend Mean changes in the annual rainfall for 2071-2099 with respect to 1961-1989, as simulated by regional climate models.
Trends Future Climate(Drying trend) 2010 2040 2041 2070 General tendency for drying (main Caribbean basin) by end of the century. Drying between 25% and 30% Possibly wetter far north Caribbean NDJ and FMA. Drying exceeds natural variability June October wet season dryer!
Trends Future Climate Drying trend 2045 Present Future Moderate Drought Severe Drought 2045 Present Future Extreme Drought
Trends Future Climate Extremes Number of simulated storms remains the same but more intense, with higher rainfall rates and increased maximum winds. Bender et al. (2010)
Trends Future Climate Even higher sea levels
Trends Future.Climate Trend Implication Feature Present Climate High temperatures Variable Rain More intense storms Rising sea levels Emergence of a Unfamiliarity new climate regime Future Climate Higher temperatures Drying trend Intense extremes Higher sea levels Entrenchment of the new climate regime Unprecedented The 2013 16 Caribbean drought is the worst multiyear period of aridity in the Caribbean and Central America since at least 1950. It was both more severe and more extensive than any other event in our dataset. This dry interval appears to be related not only to El Niño driven precipitation deficits, but also to temperature- driven increases in PET. Furthermore, station-based reports from many meteorological institutions across the Caribbean recognized the 2013 16 drought as the worst event in decades, or even in the last 100 years in some countries.
Conclusions There is an important group of future numerical simulations for the whole area of Central America and the Caribbean Several studies of sensitivity and calibration of both regional models and statistical downscaling techniques have been performed in our region resulting in a fairly important understanding of the phenomena that drive / move our climate on a regional scale and also configurations of parameterizations that adequately represent these phenomena.
Conclusions II As important messages for our region Increase in air temperature between 1 and 3.5 degrees. The increase will be greater in the summer months. Significant decrease in precipitation 25-30 % for almost the entire area of the Caribbean reaching 50% for the rainy season. For the Bahamas we expect a marginal increase. Significant increase of warm days, warm nights and a decrease of cold nights. More extreme events. Droughts, intense storms, rain, etc. Sea-level rise similar to that offered by global models.
Conclusions III Dynamic and statistical dowscaling are tools that are at our service that must be used jointly and complementarily after a rigorous analysis and know their limits and scope. Also know the uncertainties associated with the processes of generating climate change scenarios using any type of technique. Only with an integrated analysis can we give an objective assessment of the future behavior of the climate in our region.
Conclusions IV Downscaling techniques are essential to obtain regional and local climate change scenarios, especially in our geographic region, but for this exercise to be available and with the quality required by both intermediate and final users we need to have a group of conditions (requirements), without which all the effort to generate this new knowledge would be biased. More and better weather station records throughout the Caribbean. To achieve a grid point climatology for the whole area of the Caribbean and Central America (Caribbean Regional Reanalysis) Support for more numerical experiments (decrease the uncertainty associated with the generation of scenarios by using fewer members, +(members, storylines, GCM, RCM) ---> less uncertainty), more computing power and more storage power needed. Incorporate more people into the analysis of results.
Conclusions V Use all available outputs to generate products and information that can be used directly by decision makers and politicians. SMASH, CARIDRO, WG, CCORAL etc...
GRACIAS!!!!! CARiDRO Online Access http://caridro.caribbeanclimate.bz/modelling-tool/ Contacts CARiDRO Group in Cuba Abel Centella abel.centella@insmet.cu Arnoldo Bezanilla arnoldo.bezanilla@insmet.cu Alejandro Vichot alejandro.vichot@insmet.cu Jordany Morejon jordany.morejon@insmet.cu