凝结水_古尔班通古特沙漠不容忽视的水源

develop relati o nship bet w een i n terception l o ss and prec i p itati o n i n this study .Three kinds of canopy coverage such as 0.4,0.6and 0.8w ere se lected .Based on the m easure m en,t the relati o nsh ips bet w een ra i n fall interception and precipitation w ere built usi n g statistics analysis i n the eastern Q ilianshan M ountai n s .The opti m al mode ls of three k i n ds o f canopy coverage w ere selected by co m paring m any k i n ds o f statistic m ode ls .So m e conclusion cou l d be dra wn fro m the research:S-curve m odel w as selected for 0.4canopy coverage w ith corre lation coefficient (R 2

)o f 0.698.Po w er m ode lw ere the bestm odels for predicting interception a m oun t under the 0.6and 0.8canopy cover -age .There w ere h i g her co rrelati o n coeffic ients as 0.832and 0.886respective ly .W hen canopy coverage is s m al,l interception a m ount can easil y reach canopy sto rage capac ity w ith s m all precipitation.Then interception a m ount is stab le w ith the increase o f precipitation .Therefore ,S -cur ve m ode l is good fitm odel for l o w canopy coverage .H o w-ever ,interception a m ount keeps rapid increase w ith the increase of precipitation under h i g h canopy coverage .So pow er m ode l is opti m al one to esti m a te the intercep.t By co m par i n g observed value and pred i c ted value ,w e found tha t precipitation i s s m a l,l the accuracy of m odels is h igh .W hen prec i p itati o n increased,the accuracy of m edels w as decreasi n g .The rainfa ll i n tercepti o n loss has been subject o fm any stud ies .A w i d e range of f o rest types has been covered by prev i o usm easure m ent ca m paigns .L ittle i s known ,ho w ever ,about t h e i n tercepti o n loss fro m Q i n g -hai spr uce (P icea crassifolia )fo rest in the study area .Ra i n fa ll a m ountw as on l y consi d ered i n t h e study .Canopy e -vapo ration ,characteristics o f trunk storage and ra i n fa ll i n tensity taken i n to consi d ering in interception m odels w ill be e m phasized i n the future study i n hopes o f evalua ti n g eco l o g ica l and hydrlog ica l effects o fQ ingha i spr uce accu -rate l y .

K eyW ords :Q inghai spruce(P icea crassi f olia );rainfa ll interception ;statistica lm ode;l H anquangou w atershed 凝结水-古尔班通古特沙漠不容忽视的水源

干旱区降水稀少,蒸发强烈,任何补充性的水资源都可能对干旱区生态系统产生积极的影

响。在水资源匮乏的沙漠生境,除降雨之外,凝结水是重要的水分来源。近年来,中国科学院

新疆生态与地理研究所张静博士所在的课题组在古尔班通古特沙漠,针对生物结皮在凝结水

形成中的作用开展了大量的研究,发现:凝结水是生物结皮生存的重要水源,对其光合作用的

贡献也不容忽视。

张静博士通过对生物结皮影响下凝结水量和持续时间的连续日观测,研究结果表明:总凝

结水量随生物结皮发育水平呈显著增加的趋势,依次为:裸沙<藻结皮<地衣结皮<苔藓

结皮,即生物结皮的存在有利于沙漠地表凝结水的形成。凝结现象自晚上20:00~22:00开

始,次日早晨8:00结束。大多数日出后凝结现象仍继续发生。不同类型地表的凝结及蒸散过

程经历2个阶段:日出前凝结水量呈缓慢增加的趋势,日出后随温度的升高凝结水量快速减

少,其中以苔藓结皮凝结水量下降最为迅速。上述研究发表于Zhang Ji n g ,Zhang Yuan-m i n g ,

A lison Do w ning ,et a.l The i n fl u ence of b i o log ical so il cr usts on de w deposition i n Gur bantunggut

D eser,t No rthw estern China .Journa l ofH ydrology ,2009,379(3-4):220-228.376 干旱区地理 33卷