越冬期麦田根区水热耦合模型参数原位估算与检验
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摘要
越冬期根区充足的蓄水量有利于春季冬小麦的生长并有助于增产,而冬季作物根区水分运移规律通常借助土壤冻融过程水热耦合模型来描述,但该模型的预测精度受参数确定方法与边界条件等多种因素的影响。为了提高模型预测精度,提出了一种改进型的土壤冻融过程水热耦合模型参数估算方法,即运用土壤冻融特征曲线(冻土未冻水含量和土壤温度的关系)来原位估算土壤水热耦合模型参数,并检验该方法的适用性。在此基础上,评价地表蒸发量对模型预测精度的影响。大田试验在北京市昌平区小汤山精准农业示范基地开展,历经两个越冬期(2011—2012年和2012—2013年),利用管式介电传感器、温度传感器和蒸渗仪分别采集了土壤剖面未冻水含量、土壤温度和地表蒸发量数据。利用第1个越冬期(2011—2012年)的数据拟合土壤冻融特征曲线,对土壤水热参数进行最优估算,利用第2个越冬期(2012—2013年)的数据评价估算参数和地表蒸发量对模型预测精度的影响。结果表明:利用估算参数的模型预测值整体上与实测值相符。考虑到地表蒸发量对模型水热上边界的影响,第2个越冬期10 cm处未冻水含量与温度预测值和实测值的RMSE分别为0.046 m3/m3和1.883℃,20 cm深度RMSE分别为0.071 m3/m3和2.347℃。相比之下,在未考虑地表蒸发量影响下,第2个越冬期10 cm处未冻水含量与温度的模拟值和实测值的RMSE为0.059 m3/m3和2.149℃,20 cm深度RMSE为0.081 m3/m3和2.666℃。提出的改进型模型参数估算方法能够保证模型的预测精度,且考虑地表蒸发量的影响能够进一步提高模型的预测精度,随着深度的增加,蒸发量对水分与温度的影响逐渐减小。
Sufficient water storage in root zone during winter time not only benefits crop growth in next spring,but also potentially increases the yield. Water movement in root zone was often simulated by using the coupled water and heat transport(CWHT) model during soil freezing-thawing process and influenced by multiple factors such as boundary conditions,parameters determination method,and so on. An improved method based on in-situ measured data was proposed to optimally estimate the parameters in the CWHT model. The applicability of this method was validated as well. The hydraulic parameters in the model were estimated in-situ by fitting soil freezing-thawing characteristic curve(SFC),which showed the relationship between the unfrozen soil water content(USWC) and soil temperature(ST). Then,the effect of surface evaporation(Es) on prediction accuracy in winter was evaluated. The field experiment was conducted over two winters(2011—2012 and 2012—2013) in an experimental farm at Changping County,Beijing,China. The USWC,ST and Eswere monitored with dielectric tube sensors,temperature sensors and lysimeter,respectively. The data obtained in 2011—2012 were used to fit SFC to optimize the hydraulic parameters,whereas those in 2012—2013 were used to verify the model. The resultsshowed that the model simulations were agreed well with the field measurements. When considering the effects of Eson USWC and ST,the root mean square errors(RMSE) of USWC and ST predictions in2012—2013 were 0. 046 m3/m3 and 1. 883℃ at 10 cm and 0. 071 m3/m3 and 2. 347℃ at 20 cm,respectively. In contrast to the condition without Es,the RMSE for USWC and ST predictions in 2012—2013 were 0. 059 m3/m3 and 2. 149℃ at 10 cm and 0. 081 m3/m3 and 2. 666℃ at 20 cm,respectively.Thus,the improved method of parameters determination based on in-situ measured data can ensure the prediction accuracy of the CWHT model. In addition,the accuracy could be further improved with considering the effects of surface evaporation and the effect of surface evaporation on USWC and ST was gradually decreased as the depth increased.
Sufficient water storage in root zone during winter time not only benefits crop growth in next spring,but also potentially increases the yield. Water movement in root zone was often simulated by using the coupled water and heat transport(CWHT) model during soil freezing-thawing process and influenced by multiple factors such as boundary conditions,parameters determination method,and so on. An improved method based on in-situ measured data was proposed to optimally estimate the parameters in the CWHT model. The applicability of this method was validated as well. The hydraulic parameters in the model were estimated in-situ by fitting soil freezing-thawing characteristic curve(SFC),which showed the relationship between the unfrozen soil water content(USWC) and soil temperature(ST). Then,the effect of surface evaporation(Es) on prediction accuracy in winter was evaluated. The field experiment was conducted over two winters(2011—2012 and 2012—2013) in an experimental farm at Changping County,Beijing,China. The USWC,ST and Eswere monitored with dielectric tube sensors,temperature sensors and lysimeter,respectively. The data obtained in 2011—2012 were used to fit SFC to optimize the hydraulic parameters,whereas those in 2012—2013 were used to verify the model. The resultsshowed that the model simulations were agreed well with the field measurements. When considering the effects of Eson USWC and ST,the root mean square errors(RMSE) of USWC and ST predictions in2012—2013 were 0. 046 m3/m3 and 1. 883℃ at 10 cm and 0. 071 m3/m3 and 2. 347℃ at 20 cm,respectively. In contrast to the condition without Es,the RMSE for USWC and ST predictions in 2012—2013 were 0. 059 m3/m3 and 2. 149℃ at 10 cm and 0. 081 m3/m3 and 2. 666℃ at 20 cm,respectively.Thus,the improved method of parameters determination based on in-situ measured data can ensure the prediction accuracy of the CWHT model. In addition,the accuracy could be further improved with considering the effects of surface evaporation and the effect of surface evaporation on USWC and ST was gradually decreased as the depth increased.
引文
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2 SHELIA V,IM 7)UNEK J,BOOTE K,et al.Coupling DSSAT and HYDRUS-1D for simulations of soil water dynamics in the soilplant-atmosphere system[J].Journal of Hydrology and Hydromechanics,2017,66(2):232-245.
3 HARLAN R L.Analysis of coupled heat-fluid transport in partially frozen soil[J].Water Resources Research,1973,9(5):1314-1323.
4 FLERCHINGER G N,SAXTON K E.Simultaneous heat and water model of a freezing snow-residue-soil system I.Theory and development[J].Transactions of the ASAE,1989,32(2):565-571.
5 JAME Y W,NORUM D I.Heat and mass transfer in a freezing unsaturated porous medium[J].Water Resources Research,1980,16(4):811-819.
6 ZHAO L,GRAY D M,MALE D H.Numerical analysis of simultaneous heat and mass transfer during infiltration into frozen ground[J].Journal of Hydrology,1997,200(1-4):345-363.
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8 CHENG Q,SUN Y,JONES S B,et al.In situ measured and simulated seasonal freeze-thaw cycle:a 2-year comparative study between layered and homogeneous field soil profiles[J].Journal of Hydrology,2014,519:1466-1473.
9 SPAANS E J A,BAKER J M.The soil freezing characteristic:its measurement and similarity to the soil moisture characteristic[J].Soil Science Society of America Journal,1996,60(1):13-19.
10 WATANABE K,OSADA Y.Comparison of hydraulic conductivity in frozen saturated and unfrozen unsaturated soils[J].Vadose Zone Journal,2016,15(5):0154.
11 FLERCHINGER G N,SEYFRIED M S,HARDEGREE S P.Using soil freezing characteristics to model multi-season soil water dynamics[J].Vadose Zone Journal,2006,5(4):1143-1153.
12 CHENG Q,SUN Y,XUE X,et al.In situ determination of soil freezing characteristics for estimation of soil moisture characteristics using a dielectric tube sensor[J].Soil Science Society of America Journal,2014,78:133-138.
13 SUN Y,CHENG Q,XUE X,et al.Determining in-situ soil freeze-thaw cycle dynamics using an access tube-based dielectric sensor[J].Geoderma,2012,189-190(6):321-327.
14 GUO D,YANG M,WANG H.Characteristics of land surface heat and water exchange under different soil freeze/thaw conditions over the central Tibetan Plateau[J].Hydrological Processes,2011,25(16):2531-2541.
15雷志栋,尚松浩,杨诗秀.地下水浅埋条件下越冬期土壤水热迁移的数值模拟[J].冰川冻土,1998,20(1):51-54.LEI Zhidong,SHANG Songhao,YANG Shixiu.Numerical simulation on simultaneous soil moisture and heat transfer under shallow ground water table in winter[J].Journal of Glaciology and Geocryology,1998,20(1):51-54.(in Chinese)
16雷志栋,尚松浩,杨诗秀,等.土壤冻结过程中潜水蒸发规律的模拟研究[J].水利学报,1999,21(6):6-10.LEI Zhidong,SHANG Songhao,YANG Shixiu,et al.Simulation on phreatic evaporation during soil freezing[J].Journal of Hydraulic Engineering,1999,21(6):6-10.(in Chinese)
17 LI S,LAI Y,PEI W,et al.Moisture-temperature changes and freeze-thaw hazards on a canal in seasonally frozen regions[J].Natural Hazards,2014,72(2):287-308.
18 FLERCHINGER G N,SAXTON K E.Simultaneous heat and water model of a freezing snow-residue-soil system II[J].Transactions of the ASAE,1987,32(2):573-576.
19刘峻明,汪念,王鹏新,等.基于SHAW模型的冬小麦近地面层气温模拟[J/OL].农业机械学报,2015,46(增刊):274-282.http:∥www.j-csam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=2015S044&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2015.S0.044.LIU Junming,WANG Nian,WANG Pengxin,et al.Simulation of air temperature within winter wheat near-ground layer based on SHAW model[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2015,46(Supp.):274-282.(in Chinese)
20 SAITO H,IM 7)UNEK J,SCANLON B R,et al.Numerical analysis of coupled water,vapor and heat transport in the vadose zone using HYDRUS[J].Vadose Zone Journal,2006,5(2):784-800.
21 ZENG Y,SU Z,WAN L,et al.A simulation analysis of the advective effect on evaporation using a two-phase heat and mass flow model[J].Water Resources Research,2011,47,W10529,doi:10.1029/2011WR010701.
22 ZENG Y.Coupled dynamics in soil:experimental and numerical studies of energy,momentum and mass transfer[M].Berlin:Springer,2013.
23 ZHANG M,WEN Z,XUE K,et al.A coupled model for liquid water,water vapor and heat transport of saturated-unsaturated soil in cold regions:model formulation and verification[J].Environmental Earth Sciences,2016,75(8):701.
24 LI R,SHI H,FLERCHINGER G N,et al.Simulation of freezing and thawing soils in Inner Mongolia Hetao Irrigation District,China[J].Geoderma,2012,173-174:28-33.
25 CAMPBELL G S.A simple method for determining unsaturated conductivity from moisture retention data[J].Soil Science,1974,117(6):311-314.
26 DE VRIES D A.Thermal properties of soils[M]∥VAN WIJK W E.Physics of plant environment.Amsterdam:North Holland,1966:210-235.
27 FUCHS M,CAMPBELL G S,PAPENDICK R I.An analysis of sensible and latent heat flow in a partially frozen unsaturated soil[J].Soil Science Society of America Journal,1978,42(3):379-385.
28毛思帅,薛绪掌,张兴娟,等.基于称重式蒸渗仪研究早播与晚播条件下4个冬小麦品种的耗水特征[C]∥第十五次中国小麦栽培科学学术研讨会论文集,2012.
29刘荣花,朱自玺,方文松,等.冬小麦根系分布规律[J].生态学杂志,2008,27(11):2024-2027.LIU Ronghua,ZHU Zixi,FANG Wensong,et al.Distribution pattern of winter wheat root zone[J].Chinese Journal of Ecology,2008,27(11):2024-2027.(in Chinese)
30王亚萍,胡正华,张雪松,等.土壤水分胁迫对冬小麦根系分布规律的影响[J].江苏农业科学,2016,44(11):67-71.
31 WATANABE K,OSADA Y.Simultaneous measurement of unfrozen water content and hydraulic conductivity of partially frozen soil near 0℃[J].Cold Regions Science&Technology,2017,142:79-84.
2 SHELIA V,IM 7)UNEK J,BOOTE K,et al.Coupling DSSAT and HYDRUS-1D for simulations of soil water dynamics in the soilplant-atmosphere system[J].Journal of Hydrology and Hydromechanics,2017,66(2):232-245.
3 HARLAN R L.Analysis of coupled heat-fluid transport in partially frozen soil[J].Water Resources Research,1973,9(5):1314-1323.
4 FLERCHINGER G N,SAXTON K E.Simultaneous heat and water model of a freezing snow-residue-soil system I.Theory and development[J].Transactions of the ASAE,1989,32(2):565-571.
5 JAME Y W,NORUM D I.Heat and mass transfer in a freezing unsaturated porous medium[J].Water Resources Research,1980,16(4):811-819.
6 ZHAO L,GRAY D M,MALE D H.Numerical analysis of simultaneous heat and mass transfer during infiltration into frozen ground[J].Journal of Hydrology,1997,200(1-4):345-363.
7IM 7)UNEK J,GENUCHTEN M T V,WENDROTH O.Parameter estimation analysis of the evaporation method for determining soil hydraulic properties[J].Soil Science Society of America Journal,1998,62(4):894-905.
8 CHENG Q,SUN Y,JONES S B,et al.In situ measured and simulated seasonal freeze-thaw cycle:a 2-year comparative study between layered and homogeneous field soil profiles[J].Journal of Hydrology,2014,519:1466-1473.
9 SPAANS E J A,BAKER J M.The soil freezing characteristic:its measurement and similarity to the soil moisture characteristic[J].Soil Science Society of America Journal,1996,60(1):13-19.
10 WATANABE K,OSADA Y.Comparison of hydraulic conductivity in frozen saturated and unfrozen unsaturated soils[J].Vadose Zone Journal,2016,15(5):0154.
11 FLERCHINGER G N,SEYFRIED M S,HARDEGREE S P.Using soil freezing characteristics to model multi-season soil water dynamics[J].Vadose Zone Journal,2006,5(4):1143-1153.
12 CHENG Q,SUN Y,XUE X,et al.In situ determination of soil freezing characteristics for estimation of soil moisture characteristics using a dielectric tube sensor[J].Soil Science Society of America Journal,2014,78:133-138.
13 SUN Y,CHENG Q,XUE X,et al.Determining in-situ soil freeze-thaw cycle dynamics using an access tube-based dielectric sensor[J].Geoderma,2012,189-190(6):321-327.
14 GUO D,YANG M,WANG H.Characteristics of land surface heat and water exchange under different soil freeze/thaw conditions over the central Tibetan Plateau[J].Hydrological Processes,2011,25(16):2531-2541.
15雷志栋,尚松浩,杨诗秀.地下水浅埋条件下越冬期土壤水热迁移的数值模拟[J].冰川冻土,1998,20(1):51-54.LEI Zhidong,SHANG Songhao,YANG Shixiu.Numerical simulation on simultaneous soil moisture and heat transfer under shallow ground water table in winter[J].Journal of Glaciology and Geocryology,1998,20(1):51-54.(in Chinese)
16雷志栋,尚松浩,杨诗秀,等.土壤冻结过程中潜水蒸发规律的模拟研究[J].水利学报,1999,21(6):6-10.LEI Zhidong,SHANG Songhao,YANG Shixiu,et al.Simulation on phreatic evaporation during soil freezing[J].Journal of Hydraulic Engineering,1999,21(6):6-10.(in Chinese)
17 LI S,LAI Y,PEI W,et al.Moisture-temperature changes and freeze-thaw hazards on a canal in seasonally frozen regions[J].Natural Hazards,2014,72(2):287-308.
18 FLERCHINGER G N,SAXTON K E.Simultaneous heat and water model of a freezing snow-residue-soil system II[J].Transactions of the ASAE,1987,32(2):573-576.
19刘峻明,汪念,王鹏新,等.基于SHAW模型的冬小麦近地面层气温模拟[J/OL].农业机械学报,2015,46(增刊):274-282.http:∥www.j-csam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=2015S044&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2015.S0.044.LIU Junming,WANG Nian,WANG Pengxin,et al.Simulation of air temperature within winter wheat near-ground layer based on SHAW model[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2015,46(Supp.):274-282.(in Chinese)
20 SAITO H,IM 7)UNEK J,SCANLON B R,et al.Numerical analysis of coupled water,vapor and heat transport in the vadose zone using HYDRUS[J].Vadose Zone Journal,2006,5(2):784-800.
21 ZENG Y,SU Z,WAN L,et al.A simulation analysis of the advective effect on evaporation using a two-phase heat and mass flow model[J].Water Resources Research,2011,47,W10529,doi:10.1029/2011WR010701.
22 ZENG Y.Coupled dynamics in soil:experimental and numerical studies of energy,momentum and mass transfer[M].Berlin:Springer,2013.
23 ZHANG M,WEN Z,XUE K,et al.A coupled model for liquid water,water vapor and heat transport of saturated-unsaturated soil in cold regions:model formulation and verification[J].Environmental Earth Sciences,2016,75(8):701.
24 LI R,SHI H,FLERCHINGER G N,et al.Simulation of freezing and thawing soils in Inner Mongolia Hetao Irrigation District,China[J].Geoderma,2012,173-174:28-33.
25 CAMPBELL G S.A simple method for determining unsaturated conductivity from moisture retention data[J].Soil Science,1974,117(6):311-314.
26 DE VRIES D A.Thermal properties of soils[M]∥VAN WIJK W E.Physics of plant environment.Amsterdam:North Holland,1966:210-235.
27 FUCHS M,CAMPBELL G S,PAPENDICK R I.An analysis of sensible and latent heat flow in a partially frozen unsaturated soil[J].Soil Science Society of America Journal,1978,42(3):379-385.
28毛思帅,薛绪掌,张兴娟,等.基于称重式蒸渗仪研究早播与晚播条件下4个冬小麦品种的耗水特征[C]∥第十五次中国小麦栽培科学学术研讨会论文集,2012.
29刘荣花,朱自玺,方文松,等.冬小麦根系分布规律[J].生态学杂志,2008,27(11):2024-2027.LIU Ronghua,ZHU Zixi,FANG Wensong,et al.Distribution pattern of winter wheat root zone[J].Chinese Journal of Ecology,2008,27(11):2024-2027.(in Chinese)
30王亚萍,胡正华,张雪松,等.土壤水分胁迫对冬小麦根系分布规律的影响[J].江苏农业科学,2016,44(11):67-71.
31 WATANABE K,OSADA Y.Simultaneous measurement of unfrozen water content and hydraulic conductivity of partially frozen soil near 0℃[J].Cold Regions Science&Technology,2017,142:79-84.