2Co je to sucho? Neexistuje žádná přesná akceptovaná definice sucha. Obecně řečeno – nedostatek dešťových srážek oproti dlouhodobému průměru v dané oblasti, během delší časové periody (obvykle několik měsíců nebo déle), mající dopad na lidské potřeby, životní prostředí.less rainfall than is expected over an extended period of time, usually several months or longer. Or, more formally, it is a deficiency of rainfall over a period of time, resulting in a water shortage for some activity, group, or environmental sector.Very generally, it refers to a period of time when precipitation levels are low, impacting agriculture, water supply, and wildfire hazard
3Rozdělení sucha Meteorologické Zemědělské Hydrologické Socioekonomické Drought warning is further complicated by the existence of different types of drought. A meteorological drought may be identified first because of a lack of directly measured precipitation. On the other hand, socioeconomic drought is based on the premise that demand has outpaced the supply of water. Thus, a meteorological drought does not necessarily mean that there is also a socioeconomic drought (if supply is still meeting demand).
4Meteorologické suchoJe obvykle srážková odchylka od normálu během delší časové periody. Definice sucha jsou specifické pro dané oblasti. Když mluvíme o suchu obecně, myslíme tím obvykle sucho meteorologické.Meteorological drought is usually an expression of precipitation’s departure from normal over some period of time. These definitions are usually region-specific, and presumably based on a thorough understanding of regional climatology. The variety of meteorologic definitions from different countries at different times illustrates why it is folly to apply a definition of drought developed in one part of the world to another:United States (1942): less than 2.5 mm of rainfall in 48 hours Great Britain (1936): 15 consecutive days with daily precipitation totals of less than .25 mm Libya (1964): annual rainfall less than 180 mm India (1960): actual seasonal rainfall deficient by more than twice the mean deviation Bali (1964): a period of six days without rain
5Zemědělské suchoNastává, když není dostatečně vlhká půda na to aby úroda v dané období pokryla lidské požadavky. Zemědělství je obvykle prvním ekonomickým sektorem postiženým suchem.occurs when there isn’t enough soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought happens after meteorological drought but before hydrological drought. Agriculture is usually the first economic sector to be affected by drought.
6Hydrologické suchoHydrologické sucho nastává, když klesají zásoby povrchové a podpovrchové vody (vysychají vodní rezervoáry, prameny, studně). Krátkodobé deště nestačí k doplnění zásob vody. Projeví se až za několik měsíců po zemědělském suchu.Hydrologic indicators appear when surface and subsurface water supplies are below normal. As dry spells drag on, reservoirs drop and streams and wells dry up. Short-term rainfall usually isn't enough to replenish these water supplies. It takes longer for precipitation deficiencies to show up in components of the hydrological system such as soil moisture, streamflow, and ground water and reservoir levels. As a result, these impacts are out of phase with impacts in other economic sectors. For example, a precipitation deficiency may result in a rapid depletion of soil moisture that is almost immediately discernible to agriculturalists, but the impact of this deficiency on reservoir levels may not affect hydroelectric power production or recreational uses for many months. Also, water in hydrologic storage systems (e.g., reservoirs, rivers) is often used for multiple and competing purposes (e.g., flood control, irrigation, recreation, navigation, hydropower, wildlife habitat), further complicating the sequence and quantification of impacts. Competition for water in these storage systems escalates during drought and conflicts between water users increase significantly.
7Socioekonomické sucho Nastává když sucho začne ovlivňovat přímo lidi (voda na příděl, nebezpečí požárů, hydroelektrárny nefungují = vyšší ceny za elektřinu).This category refers to the situation that occurs when physical water shortage begins to affect people. Long-term droughts go beyond dead lawns. Water rationing, wildfire threats and higher hydroelectric power bills are more likely. For example, in Uruguay in 1988–89, drought resulted in significantly reduced hydroelectric power production because power plants were dependent on streamflow rather than storage for power generation. Reducing hydroelectric power production required the government to convert to more expensive (imported) petroleum and stringent energy conservation measures to meet the nation’s power needs.
8Co je to klima, klimatologie? Klima je obvykle definováno jako co je očekáváno nebo „normální“ a representuje každodenní počasí během delší časové periody (obvykle 30-ti letý průměr).Klimatologové se snaží objevit a vysvětlit dopady klimatu, aby společnost mohla plánovat své aktivity, navrhovat stavby, infrastrukturu a očekávat nepřátelské projevy klimatu.Klima je definováno stejně jako počasí teplotou, srážkami, větrem a slunečním zářením.Climate is usually defined by what is expected or “normal”, which climatologists traditionally interpret as the 30-year meanA climatologist attempts to discover and explain the impacts of climate so that society can plan its activities, design its buildings and infrastructure, and anticipate the effects of adverse conditions. Although climate is not weather, it is defined by the same terms, such as temperature, precipitation, wind, and solar radiation.Specifically, climatology answers crucial questions such as:How often does drought occur in this region?How severe have the droughts been?How widespread have the droughts been?How long have the droughts lasted?Examining water supplies and understanding the impact of past droughts help planners anticipate the effects of drought:What would happen if the drought of record occurred here now?Who are the major water users in the community, state, or region?Where does our water supply come from and how would the supplies be affected by a drought of record?What hydrological, agricultural, and socioeconomic impacts have been associated with the various droughts?How can we prepare for the next drought of record?
9Ukazatele sucha Percent of Normal Standardized Precipitation Index Palmer Drought Severity IndexCrop Moisture IndexSurface Water Supply IndexReclamation Drought IndexDecilesPercent of NormalThe percent of normal precipitation is one of thesimplest measurements of rainfall for a location.2Analyses using the percent of normal are veryeffective when used for a single region or a singleseason. Percent of normal is also easilymisunderstood and gives different indications ofconditions, depending on the location and season.It is calculated by dividing actual precipitation bynormal precipitation -- typically considered to be a30-year mean -- and multiplying by 100%. Thiscan be calculated for a variety of time scales.Usually these time scales range from a singlemonth to a group of months representing aparticular season, to an annual or water year.Normal precipitation for a specific location isconsidered to be 100%.Because of the variety in the precipitationrecords over time and location, there is no way todetermine the frequency of the departures fromnormal or compare different locations. This makesit difficult to link a value of a departure with aspecific impact occurring as a result of thedeparture, inhibiting attempts to mitigate the risksof drought based on the departures from normaland form a plan of response (Willeke et al.1994).Standardized Precipitation Index (SPI)The understanding that a deficit of precipitationhas different impacts on the ground water,reservoir storage, soil moisture, snowpack, andstreamflow led McKee et al. (1993) to developthe Standardized Precipitation Index (SPI). TheSPI was designed to quantify the precipitationdeficit for multiple time scales. These time scalesreflect the impact of drought on the availability ofthe different water resources. Soil moistureconditions respond to precipitation anomalies ona relatively short scale, while ground water,streamflow, and reservoir storage reflect thelonger- term precipitation anomalies. For thesereasons, McKee et al. (1993) originallycalculated the SPI for 3-, 6-,12-, 24-, and 48-month time scales.Overview: The SPI is an index based on theprobability of precipitation for any time scale.Who uses it: many drought planners appreciatethe SPI's versatilityPros: the SPI can be computed for different timescales, can provide early warning of drought andhelp assess drought severity, and is less complexthan the PalmerCons: values based on preliminary data may changeDeveloped by: Tom McKee, et al., ColoradoState University, 1993Monthly maps:andPalmer Drought Severity Index (PDSI)In 1965, Palmer developed an index to measurethe departure of the moisture supply (Palmer1965). Palmer based his index on the supplyand-demand concept of the water balanceequation, taking into account more than just theprecipitation deficit at specific locations. Theobjective of the Palmer Drought Severity Index(PDSI), as this index is now called, was toprovide measurements of moisture conditions thatwere standardized so that comparisons using theindex could be made between locations andbetween months (Palmer 1965).Overview: The Palmer is a soil moisturealgorithm calibrated for relatively homogeneousregionsWho uses it: many U.S. government agenciesand states rely on the Palmer to trigger droughtrelief programsPros: the first comprehensive drought indexdeveloped in the United StatesCons: Palmer values may lag emerging droughtsby several months; less well-suited formountainous land or areas of frequent climaticextremes; complex, has an unspecified, built-intime scale that can be misleadingDeveloped by: W.C. Palmer, 1965Weekly maps:products/analysis_monitoring/regional_monitoring/palmer.gifThe Palmer Index varies roughly between -6.0and Palmer arbitrarily selected theclassification scale of moisture conditions basedon his original study areas in central Iowa andwestern Kansas (Palmer 1965). Ideally, thePalmer Index is designed so that a -4.0 in SouthCarolina has the same meaning in terms of themoisture departure from a climatological normalas a -4.0 in Idaho (Alley 1984). The PalmerIndex has typically been calculated on a monthlybasis, and a long-term archive of the monthlyPDSI values for every Climate Division in theUnited States exists with the National ClimaticData Center from 1895 through the present. Inaddition, weekly Palmer Index values (actuallymodified PDSI values) are calculated for theClimate Divisions during every growing seasonCrop Moisture Index (CMI)The Crop Moisture Index (CMI) uses ameteorological approach to monitor week-toweekcrop conditions. It was developed byPalmer (1968) from procedures within thecalculation of the PDSI. Whereas the PDSImonitors long-term meteorological wet and dryspells, the CMI was designed to evaluate shorttermmoisture conditions across major cropproducing regions. It is based on the meantemperature and total precipitation for each weekwithin a Climate Division, as well as the CMIvalue from the previous week. The CMI respondsrapidly to changing conditions, and it is weightedby location and time so that maps, whichcommonly display the weekly CMI across theUnited States, can be used to compare moistureconditions at different locations.Description: A Palmer derivative, the CMIreflects moisture supply in the short term acrossmajor crop- producing regions and is notintended to assess long-term droughts.Pros: identifies potential agricultural droughtsDeveloped by: W.C. Palmer, 1968regional_monitoring/cmi.gifSurface Water Supply Index (SWSI)The Surface Water Supply Index (SWSI) wasdeveloped by Shafer and Dezman (1982) tocomplement the Palmer Index for moistureconditions across the state of Colorado. ThePalmer Index is basically a soil moisture algorithmcalibrated for relatively homogeneous regions, butit is not designed for large topographic variationsacross a region and it does not account for snow7accumulation and subsequent runoff. Shafer andDezman designed the SWSI to be an indicator ofsurface water conditions and described the indexas "mountain water dependent," in which mountainsnowpack is a major component.Description: The SWSI is designed tocomplement the Palmer in the state of Colorado,where mountain snowpack is a key element ofwater supply; calculated by river basin, based onsnowpack, streamflow,Pros: represents water supply conditions uniqueto each basinCons: changing a data collection station or watermanagement requires that new algorithms becalculated, and the index is unique to each basin,which limits interbasin comparisonsDeveloped by: Shafer and Dezman, 1982Reclamation Drought IndexThe Reclamation Drought Index (RDI) wasrecently developed as a tool for defining droughtseverity and duration, and for predicting the onsetand end of periods of drought. The impetus todevise the RDI came from the Reclamation StatesDrought Assistance Act of 1988, which allowsstates to seek assistance from the Bureau ofReclamation to mitigate the effects of drought.Description: like the SWSI, the RDI iscalculated at the river basin level, incorporatingtemperature as well as precipitation, snowpack,streamflow and reservoir levels as inputWho uses it: the Bureau of Reclamation, theState of Oklahoma as part of their drought planPros: by including a temperature component, italso accounts for evaporationCons: because the index is unique to each riverbasin, interbasin comparisons are limitedDeveloped by: the Bureau of Reclamation, as atrigger to release drought emergency relief fundsDecilesArranging monthly precipitation data into decilesis another drought-monitoring technique. It wasdeveloped by Gibbs and Maher (1967) to avoidsome of the weaknesses within the "percent ofnormal" approach. The technique they developeddivided the distribution of occurrences over along-term precipitation record into tenths of thedistribution. They called each of these categoriesa "decile." The first decile is the rainfall amountnot exceeded by the lowest 10% of theprecipitation occurrences. The second decile isthe precipitation amount not exceeded by the9Description: groups monthly precipitationoccurrences into deciles, so by definition,"much lower than normal" weather can't occurmore often than 20 percent of the timeWho uses it: AustraliansPros: provides an accurate statisticalmeasurement of precipitationCons: accurate calculations require a longclimatic data recordDeveloped by: Gibbs and Maher, 1967lowest 20% of occurrences. These decilescontinue until the rainfall amount identified by thetenth decile is the largest precipitation amountwithin the long-term record. By definition, the fifthdecile is the median, and it is the precipitationamount not exceeded by 50% of the occurrencesover the period of record. The deciles aregrouped into five classifications.
10Předpověď suchaBěhem události ENSO (El Niño–Southern Oscillation) mohou nastat sucha téměř všude na světě, vědci nalezli nejsilnější spojení mezi ENSO a suchem v Austrálii, Indii, Indonésii, Brazílii, v části jižní a východní Afriky, oblastmi v Pacifiku, střední Amerikou a různými částmi USA. ENSO události zdá se mají silný vliv na oblasti v nižších zem. šířkách, obzvláště v rovníkovém Pacifiku a okolních tropických územích. Intenzita anomálií v mírném pásmu není tolik souvislá s ENSO jako v nižších zem. šířkách.Nyní se měří na spousta místech v Pacifiku teplota, proudy a vítr a na základě těchto dat se vytváří počítačové simulace.Vědci v současné době nejsou schopni na většině míst předpovědět sucha na měsíc a více dopředu. Predikce sucha je závislá na srážkách a teplotě.ENSO and Drought Around the World During an ENSO event, drought can occur virtually anywhere in the world, though researchers have found the strongest connections between ENSO and intense drought in Australia, India, Indonesia, the Philippines, Brazil, parts of east and south Africa, the western Pacific basin islands (including Hawaii), Central America, and various parts of the United States. Drought occurs in each of the above regions at different times (seasons) during an event and in varying degrees of magnitude.Ropelewski and Halpert also looked at the link between ENSO events and regional precipitation patterns around the globe (1987). Northeastern South America from Brazil up to Venezuela shows one of the strongest relationships. In 17 ENSO events, this region had 16 dry episodes. It is not uncommon to find the rain forests burning during these dry periods. Other areas from their study also showed a strong tendency to be dry during ENSO events. In the Pacific basin, Indonesia, Fiji, Micronesia, and Hawaii are usually prone to drought during an event. Virtually all of Australia is subjected to abnormally dry conditions during ENSO events, but the eastern half has been especially prone to extreme drought. This is usually followed by bush fires and a decimation of crops. India has also been subjected to drought through a suppression of the summer monsoon season that seems to coincide with ENSO events in many cases. Eastern and southern Africa also showed a strong correlation between ENSO events and a lack of rainfall that brings on drought in the Horn region and areas south of there. Another region they found to be abnormally dry during warm events was Central America and the Caribbean Islands.Thus, ENSO events seem to have a stronger influence on regions in the lower latitudes, especially in the equatorial Pacific and bordering tropical areas. The relationships in the mid-latitudes aren’t as pronounced nor are they as consistent in the way wet or dry weather patterns are influenced by El Niño. The intensity of the anomalies in these regions is also more inconsistent than those of the lower latitudes. NOAA’s Climate Prediction Center has short papers on the typical impacts associated with ENSO and La Niña episodes.Can We Predict ENSO? If we can understand some of the teleconnections discussed above, it can lead us to some general predictive capabilities via numeric computer models that can help us determine and conclude when conditions are favorable for the onset of an event. Numeric models try to emulate processes (and dynamic relationships) that occur in nature using sets of numbers and equations. But once an event is underway, forecasting its duration and intensity are difficult at best.Scientists don’t know how to predict drought a month or more in advance for most locations. Predicting drought depends on the ability to forecast two fundamental meteorological surface parameters, precipitation and temperature.
11Dopady suchaDělíme na přímé a nepřímé, ekonomické, environmentální a sociální.Přímé – snížená produktivita půdy, zvýšení rizika požárů, snížení vodní hladiny, zvýšená úmrtnost zvířat atd.Nepřímé jsou následky přímých – snížený příjem zemědělců, zvýšení ceny dřeva a jídla, nezaměstnanost, zvýšená kriminalita, migrace lidí atd.Ekonomické – z hlediska peněz -úhyn zeměděl. zvířat, ryb, rostlin, zvýšení cen energie, jídla, snížení výnosů z turistiky a rekreace atd.Environmentální – z hlediska degradace krajiny - zvýšení rizika požárů, degradace půdy, nedostatek pitné vody, migrace a úhyn zvěře.Sociální – dopad na lidi – zhoršení zdraví lidí, zvýšení konfliktů, snížená kvalita života, vzrůst chudoby, migrace lidí.In fact, the U.S. Federal Emergency Management Agency has estimated that drought costs the United States an average of $6-8 billion dollars every year, making it the costliest natural disaster. Losses from the 2002 drought may be as much as $20-30 billion.When drought occurs, it can have many far-reaching impacts. That's because water is an important part of so many of our activities. We need water for everything from human, wildlife, and plant health; to washing dishes, river rafting, and fishing; to growing food, cooling engines, and producing electricity. When we don't have enough water for these activities, there will most often be a negative impact.But drought does not always affect everyone negatively. Well drillers, for example, may be more in demand, and construction companies may have fewer rainy days to slow down their building progress. To prepare for drought, people need to figure out how drought will affect their own particular interests or activities.Types of Drought Impacts Drought impacts are often grouped as economic, environmental, and social. When we talk of economic impacts, we mean those impacts of drought that cost people (or businesses) money. For example:Farmers may lose money if a drought destroys their crops or stunts the crops' growth, causing lower yields and poor crop quality. If a farmer's water supply is too low, the farmer may have to spend more money on irrigation or to find new water sources, like wells.Ranchers may lose livestock, or they might have to spend more money on feed and water for their animals.People who work in the timber industry may be affected when trees, especially young trees, die or wildfires destroy stands of timber.Businesses that manufacture and sell recreational equipment, like boats and fishing equipment, may not be able to sell some of their goods because drought has dried up lakes and other water sources.Businesses that depend on agricultural production, like tractor manufacturers and companies that process food, may lose business when drought damages crops or livestock.Power companies that normally rely on hydroelectric power (electricity that's created from the energy of running water) may have to spend more money on other fuel sources if drought dries up too much of the water supply. The power companies' customers would also have to pay more.Water companies may have to spend money on new or additional water supplies.Barges and ships may have difficulty navigating streams, rivers, and canals because of low water levels, which would also affect businesses that depend on water transportation for receiving or sending goods and materials.People may have to pay more for food.Drought also causes environmental losses because of forest fires; soil erosion; damage to plants, animals, and their habitat; and air and water quality decline. Sometimes the damage is only temporary, and conditions return to normal when the drought is over. But sometimes drought's impact on the environment can last a long time, or may even become permanent if, for example, an endangered species was lost because of low stream flows. Examples of environmental impacts include:Losses or destruction of fish and wildlife habitatLack of food and drinking water for wild animalsIncrease in disease in wild animals, because of reduced food and water suppliesMigration of wild animals, leading to a loss of wildlife in some (drought-stricken) areas and too many wildlife in areas not affected by droughtIncreased stress on endangered speciesLower water levels in reservoirs, lakes, and pondsLoss of wetlandsMore firesWind and water erosion of soils, reduced soil qualitySocial impacts of drought include public safety, health, conflicts that arise between people when there isn't enough water to go around, and changes in lifestyle. Many of the impacts that we consider economic and environmental also have social impacts. Examples of social impacts include:Mental and physical stress on people (for example, people may experience anxiety or depression about economic losses caused by drought)Health problems related to low water flows (for example, low water supplies and water pressure make fire fighting more difficult)Loss of human life (from heat stress and suicides, for example)Threat to public safety from an increased number of forest and range firesReduced incomesPopulation migrations (from rural to urban areas)Fewer recreational activities
12Dopady sucha na kontinenty FEMA has estimated that drought costs the United States $6–8 billion annually (FEMA, 1995). Federal Emergency Management Agency
17Colorado 2002This is what remains of Barr Lake along I-76 northeast of Denver. The wooden dock is stranded well away from the water.
18Země s nedostatkem obnovitelných zdrojů vody Spotřeba vody na člověka v ČR za den cca 130l.
19PrevenceŠetřit s vodou – nevylévat zbytečně vodu, když ji lze použít ještě někde jinde (k zalití květin, nebo mytí).Zkontrolovat jestli nám někde nekape voda.Místo mytí se ve vaně se sprchovat, nesprchovat se zbytečně dlouho, používat úspornou hlavu s malým průtokem vody.Úsporné splachování záchodu.Nezalívat zbytečně často trávník.Xeriscaping – rostliny odolné vůči suchu.DROUGHT SAFETY TIPS To conserve water indoors and outdoors:Never pour water down the drain when there may be another use for it such as watering a plant or garden, or for cleaning.Verify that your home is leak free.Take shorter showers. Replace your showerhead with an ultra-low-flow version.Don't let water run while shaving or washing your face. Brush your teeth first while waiting for water to get hot, then wash or shave after filling the basin.Don't overwater your lawn. As a general rule, water every five to seven days in the summer and every 10 to 14 days in the winter.Plant it smart. Use Xeriscape landscaping. For more information on Xeriscape landscaping contact your water management district.Water lawns during the early morning hours when temperatures and wind speed are the lowest. This reduces losses from evaporation.Promote water conservation in community newsletters, on bulletin boards and by example. Encourage your friends, neighbors and co-workers to "do their part."Don't assume - even if you get your water from a private well - that you need not observe good water use rules. Every drop counts.Facts on water use in and around our homesCanadians use an average of 335 litres of water each day for household and gardening purposes. The United States uses around 380 litres; Israel uses 135 litres.Only 10% of our home water supply is used in the kitchen for drinking, cooking and washing dishes.About 65% of indoor home use occurs in the bathrooms.Toilets use 40% more water than needed.The greatest water use occurs in the summer when about half to three quarters of treated water is sprayed on lawns.