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Click to edit Master title styleCAUSES OF DROUGHT• Click ‣ Man-made to edit (supply Master vs demand)text styles‣ Natural• Second level- Climatic variations (temp and rainfall)• Third level- Large-scale variations in atmosphere(ENSO, NAO)• Fourth level‣ Change in the jet stream patterns‣ Change in ocean curents• Fifth level‣ Earth-atmosphere feedbacks Determining the links between “climate” and “weather” (precipitation)variability is vital to understanding the causes of droughts.WMODrought and Desertification Workshop, Alanya, 14-16 November 20061TSMS

The “Climate - Weather” ConnectionClick to edit Master title styleUnderstanding the links between “climate” and “weather”(precipitation) variability is vital to identifying the causes ofdroughts.• Click to edit Master text styles• To understand droughts, need to understand dominant regional andseasonal • Second precipitation level mechanisms (synoptic-scale, convective,orographic --)• Third level• As droughts evolve, they may have feedback effects on T andprecip., both locally and non-locally, that effect the weather:• Fourth level• Fifth level- T: higher maxs., larger diurnal cycles -- P: “In times of drought, all signs of rain fail.”WMODrought and Desertification Workshop, Alanya, 14-16 November 20062TSMS

Predicting Drought at regional baseClick to edit Master title style meteorological drought is never the result of a single cause. It is the result of many causes, often synergisticin nature. too many variables:- air-sea interactions- soil moisture and land surface processes,- topography,• Click to edit Master text styles- the accumulated influence of dynamically unstable synoptic weather systems at the global scale.- differs by region, season, and climatic regime• Second levelThe Big Picture: Global Weather Patterns interacting systems or teleconnections El Niño/Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO)• Third levelThe Little Picture: High Pressure• Fourth level The immediate cause of drought is the predominant sinking motion of air (subsidence) that results incompressional warming or high pressure,- inhibits cloud formation• Fifth level- results in lower relative humidity and less precipitation. Regions under the influence of semipermanent highpressure are usually deserts, such as the Sahara. Most climatic regions experience varying degrees of dominance by high pressure, often depending on theseason. Prolonged droughts occur when large-scale anomalies in atmospheric circulation patterns persist for monthsor seasons (or longer).WMODrought and Desertification Workshop, Alanya, 14-16 November 20063TSMS

Atmospheric Convection and Subtropical DesertsClick to edit Master title styleTropopause Barrier• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelRAINWMODrought and Desertification Workshop, Alanya, 14-16 November 20064TSMS

c. Time scalesClick to edit Master title styleDroughts• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelDroughts span a broad range of time scales, from short-term “flash droughts” that mayhave significant agricultural impacts, to multi-year or even decadal droughts (1930s, 1950s,etc.)WMODrought and Desertification Workshop, Alanya, 14-16 November 20066TSMS

El Nino/Southern ~Oscillation (ENSO) is a primarymode of Pacific climate variabilityClick to edit Master title style• Click to edit Master text styles• Second level• Third levelcool• Fourth level• Fifth levelENSO Sea-Surface Temperatures~ ~warmwarmcoolWMODrought and Desertification Workshop, Alanya, 14-16 November 20067TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 20068TSMS

Empirical estimates of changes in risks ofseasonal precipitation extremesMarch-MayClick to edit Master title style(constructed from CDC website:http://www.cdc.noaa.gov/Climaterisks/)• Click El to Niñoedit Master text styles• Second level• Third level• Fourth level• Fifth levelLa NiñaWMODrought and Desertification Workshop, Alanya, 14-16 November 20069TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200610TSMS

THERE IS A COLLECTIVE PICTURE OF A WARMING WORLD,& HUMAN ACTIVITIES HAVE CONTRIBUTEDClick to edit Master title style• Points . . .• Click to edit Master text styles Global temperatures: Up 0.7 – 1.4 o over past 100 years• Second level Consistent with the warming:• Glacial retreat in the Arctic• 10-15% reduction in Arctic sea iceextent (1970s)• Third level• Snow-cover decrease (10% since1970s)• Freeze-free periods lengthened•(20th Fourth century)level• Sea-level increased 4-8 inches(since 19th century)• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200611TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200612TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWARMING OVER THE PAST50 YEARS IS RELATED TO GREENHOUSEGAS INCREASES• Reasons . . .Comparisons of simulatedvs. observed temperatures: Simulations with natural and humanfactors match observations best Correspondences increase with time Probability is low that a “natural only”Earth would have such correspondences.Q: What could thismean for the future?WMODrought and Desertification Workshop, Alanya, 14-16 November 200613TSMS

What about the Future?Click to edit Master title styleGlobal climate change will have various consequences for natural andhuman systems In general, it will lead to an intensification of the water cycleenhanced • Click frequencies to edit of Master floods and extreme text styles precipitation events inregions traditionally prone to this threat..• Second level increased water scarcity in already water deficient regions of the world..• Third level Shifts in the amount and timing of precipitation will have severeconsequences for arid to semi-arid regions..• Fourth level As temperatures increase, it may lead to more intense droughts duringperiods of dry weather due to increases in evaporation..• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200614TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200615TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200616TSMS

CONTRIBUTING FACTORS TO DROUGHT IN TURKEYClick to edit Master title style low rainfall and untimely rainfall some links to the regional circulation patterns• Click - NAOto edit Master text styles- ENSO• Second level Weakening of Siberia Anticyclone (winter droughts) • Penetration Third level of Azor Anticyclone ridge into Eastern Mediterranen Decrease in intensity and frequency of frontal systems• Fourth leveloriginating from Atlantic • Penetration Fifth level of Basra low pressure systems further into north(summer droughts) Strengtening of Basra low pressure systems (summer droughts)WMODrought and Desertification Workshop, Alanya, 14-16 November 200617TSMS

mPMAJOR AIR MASSES THAT AFFECT CLIMATE OF TURKEYClick to edit Master title styleContinentalPOLAR• Click to edit Master text styles• Second level• Third level• Fourth levelmTmP• Fifth levelT R O P I C A L(warm)(Cold)Originates from Atlantic OceanCauses unstable moisture conditionsBrings rain to Black-Sea region while causingsnowfall in central partsWarm and moistBrings rain to the western partscTcPDry and coldWith the moisture it takesover Black-Sea, it causesorographic precipitationContinentalHot and dryIf meets northerly flows,it may produce rainfallWMODrought and Desertification Workshop, Alanya, 14-16 November 200618TSMS

CHANGES IN CIRCULATION PATTERNSClick to edit Master title styleAtlantic(Iceland)• LowClick to edit Master text styles• Second level• Third level• Fourth level• Fifth levelPenetration ofAzor Anticyclone ridge toE. MediterraneanSlide 30Weakening ofSiberia HighPenetration ofBasra Low tofurther northWMODrought and Desertification Workshop, Alanya, 14-16 November 200619TSMS

TOPOGRAPHY OF TURKEYClick to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200620TSMS

NORTH ATLANTIC OSCILLATIONClick to edit Master title style The NAO is the dominant mode of winter climate variability in the North Atlantic regionranging from central North America to Europe and much into Northern Asia. The NAO is a large scale seesaw in atmospheric mass between the subtropical highand the •polar Clicklow. The tocorresponding edit Masterindex varies textfrom stylesyear to year, but alsoexhibits a tendency to remain in one phase for intervals lasting several years.• Second level• Third level• Fourth level• Fifth levelWMODrought and Desertification Workshop, Alanya, 14-16 November 200621TSMS

Click to edit Master title style• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth level The Positive NAO index phaseshows a stronger than usualsubtropical high pressure centerand a deeper than normal Icelandiclow. The increased pressuredifference results in more andstronger winter storms crossing theAtlantic Ocean on a more northerlytrack. This results in warm and wetwinters in Europe and in cold anddry winters in northern Canada andGreenlandWMODrought and Desertification Workshop, Alanya, 14-16 November 200622TSMS

Click to edit Master title stylepathway.• Click to edit Master text styles• Second level• Third level• Fourth level• Fifth level The negative NAO index phase: aweak subtropical high and a weakIcelandic low. The reduced pressure gradientresults in fewer and weaker winterstorms crossing on a more west-east They bring moist air into theMediterranean and cold air tonorthern Europe The US east coast experiencesmore cold air outbreaks and hencesnowy weather.WMODrought and Desertification Workshop, Alanya, 14-16 November 200623TSMS

RELATIONSHIP BETWEEN ANNUAL PRECIPITATION AND NAOClick to edit Master title style• Click to edit Master text styles• Second 43levelNAO INDEX521• Third level0-1-2• Fourth level-3-4• Fifth level193019341938RELATIONSHIP BETWEEN LONG-TERM RAINFALLANOMALIES OF TURKEY AND NAO INDEX19421946195019541958196219661970YEARS19741978198219861990199419982002200150100500-50-100-150-200RAINFALLANOMALIES (MM)NAO INDEXRAINFALL ANOMALIESWMODrought and Desertification Workshop, Alanya, 14-16 November 200624TSMS