摘要
针对西藏地区地域广阔、辐射站点少且分布不均匀等特征,为获得适用于西藏主要农业区的太阳总辐射计算模型参数,基于拉萨、狮泉河、那曲、昌都站1961—2004年的逐日太阳总辐射及日照时数数据,采用最小二乘法对?ngstr?m-Prescott(AP)中的参数进行率定,利用2005—2016年的逐日观测数据对率定结果进行验证,并根据不同农业区划,由已知站点的参数值推求无辐射数据典型站点的经验参数,进而选取不同农业区划的经验参数。结果表明,FAO推荐的参数值并不完全适用于西藏地区,4个站点2个参数率定值的变化范围分别为0.18～0.26以及0.55～0.64。经验参数受纬度影响最大,其次是经度、海拔。拉萨站和昌都站计算值与实测值的吻合较好。5个不同农业区2个参数值变化范围分别为0.18～0.25及0.55～0.64。FAO推荐值在高原温带半湿润区以及高原温带半干旱区适用性较好。该研究成果可为无辐射实测地区的太阳辐射值和作物腾发量的计算提供依据。
In Tibet,radiation stations are scare.The radiation is important for accuracy estimation of reference evapotranspiration.In this study,the parameters of typical Agstrom-Prescott(AP)equation were estimated and FAO recommended values were evaluated for its applicability in Tibet agricultural region.The data of daily solar radiation and sunshine hours from 1961 to 2016 were from all the 4 radiation stations(Lhasa,Shiquanhe,Nagchu and Chamdo stations)in Tibet.The AP parameters were fitted by nonlinear least square method.The data from the years of 1961 to 2004 were for calibration and those from the year of 2005 to 2016 were for validation.Standard deviation(SD),mean absolute error(MAE)and mean absolute percentage error(MAPE)were used for model accuracy evaluation in order to find the main factor affecting parameter change.In addition,the relationships between parameters and longitude,latitude and altitude were analyzed.The stations were in 2 climatic regions of plateau temperate semi-arid zone and plateau cold arid zone.According to the Tibet Agricultural Climatic Zoning,5 zones were classified in Tibet,which included plateau temperate semi-humid zone,plateau cold arid zone,plateau temperate semi-arid zone,plateau warm-cool semi-humid zone and plateau temperate arid zone.Representative stations were chosen for these zones.Nyingchi,Shigatse,Suo county,Shiquanhe and Nagchu were for plateau temperate semi-humid zone,plateau temperate semi-arid zone,plateau warm-cool semi-humid zone,plateau temperate arid zone and plateau cold arid zone,respectively.Based on the relationship between main factor and parameters,the parameters for the other 3 zones were estimated by using inverse distance weighted method.The deviations from FAO recommended values were used for evaluation of FAO recommendations.The results showed that the SD,MAE and MAPE were in the acceptable range and the validation results for SD and MAE were 1.75-2.80 MJ/(m^2·d),1.27-2.03 MJ/(m^2·d),respectively.The MAPE was closer or slightly different from 0.It indicated that the AP model was reliable for estimation of radiation.The calibrated coefficients for these 4 stations ranged from 0.18 to 0.26 and from 0.55 to 0.64,respectively.The recommended values by FAO were not always suitable in Tibet with the deviation of-28%-28%.The coefficient of variation of coefficient recommended by past studies was 15%-20%.Compared to previous studies with shorter time period,our results were more reliable since the time duration(about 50 years)was longer.The parameters were closely correlated with latitude with the determination coefficient higher than 0.6 but they were less related with longitude and altitude with the determination coefficient less than 0.2.Based on latitude,the interpolation was conducted for Nyingchi,Shigatse and Suo county.Finally the AP coefficients for 5 different agricultural zones were obtained and they ranged from 0.18 to 0.25 and from 0.55 to 0.64,respectively.The deviation analysis showed that the FAO recommended values had a good applicability in the plateau temperate semi-humid zone,plateau cold arid zone and plateau temperate semi-arid zone.The results can provide valuable information for the calculation of solar radiation and reference evapotranpiration in the areas without measured radiation data in Tibet.
作者
罗红英
李丹
崔远来
田正野
罗玉峰
Luo Hongying;Li Dan;Cui Yuanlai;Tian Zhengye;Luo Yufeng(Water Conservancy Project & Civil Engineering College,Tibet Agriculture & Animal Husbandry University,Nyching 860000,China;State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2019年第3期149-155,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(51769035)
西藏自治区科技厅地区自然科学基金项目(ZH20170006)
西藏农牧学院2015年柔性引进人才项目
西藏自治区第三批重点科技计划项目经费资助
