光谱学与光谱分析
光譜學與光譜分析
광보학여광보분석
SPECTROSCOPY AND SPECTRAL ANALYSIS
2014年
12期
3391-3396
,共6页
程晓娟%杨贵军%徐新刚%陈天恩%李振海%冯海宽%王冬
程曉娟%楊貴軍%徐新剛%陳天恩%李振海%馮海寬%王鼕
정효연%양귀군%서신강%진천은%리진해%풍해관%왕동
VWC%EWT%冠层光谱%NDWI%冬小麦
VWC%EWT%冠層光譜%NDWI%鼕小麥
VWC%EWT%관층광보%NDWI%동소맥
Vegetation water content(VWC)%Equivalent water thickness(EWT)%Canopy spectral%NDWI(Normalized Different Water Index)%Winter w heat
水分含量是表征作物水分胁迫生理状况的重要指标,及时有效地监测作物水分含量对于评估作物水分盈亏平衡,指导农业生产灌溉具有重要意义。针对不同形式的归一化差值水分指数(NDWI)存在的饱和性问题,拟引入增强型植被指数EVI对其加以适当改进,通过构建新的植被水分指数NDWI#(即NDWI*EVI)来估算作物水分含量。首先,利用PROSAIL辐射传输模型分析了由不同水分敏感波段(1240,1450,1950和2500 nm)构建的各种典型NDWIs与相应新植被水分指数NDWI#对植被冠层水分及LAI的饱和响应特征;然后,利用田间实验光谱和水分数据,开展作物水分含量的建模和验证分析。结果表明:将EVI引入后,形成的新水分指数 NDWI#能够有效提高冬小麦水分含量估算精度,特别是针对 NDWI1450,ND-WI1940,NDWI2500这三个指数,改进后的新指数显著提高了对LAI响应的饱和点,冬小麦作物水分估算精度也得到较为的明显改善。研究表明,将含有可见光波段信息的EVI引入到NDWI中,构建的新指数NDWI#因融合可见光、近红外和短波红外更多波段的光谱信息,对估算冬小麦冠层含水量可能具有更好的优势。
水分含量是錶徵作物水分脅迫生理狀況的重要指標,及時有效地鑑測作物水分含量對于評估作物水分盈虧平衡,指導農業生產灌溉具有重要意義。針對不同形式的歸一化差值水分指數(NDWI)存在的飽和性問題,擬引入增彊型植被指數EVI對其加以適噹改進,通過構建新的植被水分指數NDWI#(即NDWI*EVI)來估算作物水分含量。首先,利用PROSAIL輻射傳輸模型分析瞭由不同水分敏感波段(1240,1450,1950和2500 nm)構建的各種典型NDWIs與相應新植被水分指數NDWI#對植被冠層水分及LAI的飽和響應特徵;然後,利用田間實驗光譜和水分數據,開展作物水分含量的建模和驗證分析。結果錶明:將EVI引入後,形成的新水分指數 NDWI#能夠有效提高鼕小麥水分含量估算精度,特彆是針對 NDWI1450,ND-WI1940,NDWI2500這三箇指數,改進後的新指數顯著提高瞭對LAI響應的飽和點,鼕小麥作物水分估算精度也得到較為的明顯改善。研究錶明,將含有可見光波段信息的EVI引入到NDWI中,構建的新指數NDWI#因融閤可見光、近紅外和短波紅外更多波段的光譜信息,對估算鼕小麥冠層含水量可能具有更好的優勢。
수분함량시표정작물수분협박생리상황적중요지표,급시유효지감측작물수분함량대우평고작물수분영우평형,지도농업생산관개구유중요의의。침대불동형식적귀일화차치수분지수(NDWI)존재적포화성문제,의인입증강형식피지수EVI대기가이괄당개진,통과구건신적식피수분지수NDWI#(즉NDWI*EVI)래고산작물수분함량。수선,이용PROSAIL복사전수모형분석료유불동수분민감파단(1240,1450,1950화2500 nm)구건적각충전형NDWIs여상응신식피수분지수NDWI#대식피관층수분급LAI적포화향응특정;연후,이용전간실험광보화수분수거,개전작물수분함량적건모화험증분석。결과표명:장EVI인입후,형성적신수분지수 NDWI#능구유효제고동소맥수분함량고산정도,특별시침대 NDWI1450,ND-WI1940,NDWI2500저삼개지수,개진후적신지수현저제고료대LAI향응적포화점,동소맥작물수분고산정도야득도교위적명현개선。연구표명,장함유가견광파단신식적EVI인입도NDWI중,구건적신지수NDWI#인융합가견광、근홍외화단파홍외경다파단적광보신식,대고산동소맥관층함수량가능구유경호적우세。
Moisture content is an important indicator for crop water stress condition ,timely and effective monitoring crop water content is of great significance for evaluate crop water deficit balance and guide agriculture irrigation .In order to improve the sat-urated problems of different forms of typical NDWI (Normalized Different Water Index ) ,we tried to introduce EVI (Enhanced Vegetation Index) to build new vegetation water indices(NDWI# ) to estimate crop water content .Firstly ,PROSAIL model was used to study the saturation sensitivity of NDWIs and NDWI# to canopy water content and LAI(Leaf Area Index) .Then ,the es-timated model and verified model were estimated using the spectral data and moisture data in the field .The result showed that the new indices have significant relationships with canopy water content .In particular ,by implementing modified standardized for NDWI1 450 ,NDWI1 940 ,NDWI2 500 .The result indicated that newly developed indices with visible-infrared and shortwave infra-red spectral feature may have greater advantage for estimation winter canopy water content .