模拟太阳辐射减弱对不同播期冬小麦田N2O排放影响及光谱估算
Effects of Sowing Dates on N2O Emissions from Winter Wheat Fields under Different Shading Conditions
马莉 1娄运生 2王勇 3杨晓军 3李君 4马绎皓 3沙宏娥 3李睿 4张震4
作者信息
- 1. 南京信息工程大学 气象灾害预报预警与评估协同创新中心,江苏 南京 210044;兰州中心气象台,甘肃 兰州 730020
- 2. 南京信息工程大学 气象灾害预报预警与评估协同创新中心,江苏 南京 210044;南京信息工程大学 江苏省农业气象重点实验室,江苏 南京 210044
- 3. 兰州中心气象台,甘肃 兰州 730020
- 4. 南京信息工程大学 江苏省农业气象重点实验室,江苏 南京 210044
- 折叠
摘要
太阳辐射减弱是全球气候变化的主要特征之一.太阳辐射减弱对农田氧化亚氮(N2O)排放有何影响以及能否基于高光谱遥感进行估算,尚未见报道.通过田间模拟试验,探讨了不同遮阴强度下不同播期对冬小麦田N2O排放的影响及基于冠层高光谱变量估算N2O排放通量.采用普通黑色遮阳网覆盖冬小麦植株冠层,以模拟太阳辐射减弱.遮阴强度设3个水平,即对照(CK,不遮阴,遮阴率为0)、中度遮阴(S1,遮阴率为61.85%)和重度遮阴(S2,遮阴率为83.91%);播期设2个水平,即常规播期(T)和晚播(L).结果表明:①遮阴显著提高了冬小麦农田N2O排放量,即S2>S1>CK;晚播明显降低麦田N2O排放量.②冬小麦冠层光谱反射率与N2O排放通量的敏感波段,主要在红光波段和近红外波段,拔节期呈显著正相关,最大相关系数为0.92,孕穗—抽穗期呈显著负相关,最大负相关为-0.75.6种植被指数与N2O排放通量呈显著相关性,其中NLI(非线性植被指数)与N2O排放通量的相关系数最佳,为0.93(拔节期)、-0.77(孕穗—抽穗期).③于拔节期建立了以NLI和629、630 nm原始反射率(ρ 629、ρ 630)为参数估算N2O排放通量的逐步回归模型,建模集和验证集决定系数R2 分别为0.89和0.83;于孕穗—抽穗期建立了以ρ 1072、ρ 760 为参数估算N2O排放通量的双变量模型,R2 分别为 0.70和 0.75.研究认为,通过构建高光谱遥感参数模型估算农田N2O排放量是可行的,这为进一步开展区域农田N2O排放量遥感监测提供了试验参考依据.
Abstract
Solar radiation reduction is one of the main features of global climate change.Few researches have been available regarding the impact of reduced solar radiation on Nitrous Oxide(N2O)emissions and its estima-tion based on hyperspectral remote sensing under field conditions.Field simulation experiment was conducted to investigate the effects of sowing date on N2O emission in winter wheat field under different shading intensities and N2O emission flux estimation based on canopy hyperspectral variables.Ordinary black sunshade net was used to cover the canopy of winter wheat plants to simulate the decrease of solar radiation.The shading intensity was set at three levels,namely,control(CK,no shading,0%shading rate),moderate shading(S1,61.85%shading rate)and heavy shading(S2,83.91%shading rate).The sowing date was set at two levels,namely,traditional sowing date(T)and late sowing date(L).The results showed that:(1)shading significantly in-creased N2O emission,i.e.S2>S1>CK;but late sowing significantly reduced N2O emission in winter wheat field.(2)The sensitive bands between spectral reflectance on winter wheat canopy and N2O flux are mainly in the red band and near-infrared band.A significant positive correlation existed at the elongation stage,with the maximum correlation coefficient of 0.92.A significant negative correlation occurred at booting-heading stage,with the maximum negative correlation of-0.75.The significant correlations were observed between six plant-ing cover indexes and N2O fluxes,and the highest correlation coefficient was found between NLI(nonlinear vegetation index)and N2O flu,with being 0.93(jointing stage)and-0.77(booting to heading stage).(3)At the elongation stage,a stepwise regression model was established to estimate N2O flux using NLI and original reflectance(ρ 629、ρ 630)at 629 nm and 630 nm.The coefficient of determination(R2)of modeling set and verifica-tion set was 0.89 and 0.83,respectively.At booting and heading stage,a bivariate model was established to esti-mate N2O flux using the parameters(ρ 1072、ρ 760),with R2 being 0.70 and 0.75,respectively.This study suggests that it is feasible to estimate N2O emission in winter wheat field by hyperspectral remote sensing parameter mod-el,and to provide experimental reference for further monitoring regional N2O emissions with remote sensing.
关键词
N2O排放通量/高光谱变量/太阳辐射减弱/播期/冬小麦Key words
Solar radiation weakening/N2O flux/Hyperspectral variable/Sowing date/Winter wheat引用本文复制引用
基金项目
国家自然科学基金(41875177)
国家自然科学基金青年基金(42205083)
大学生创新创业训练计划项目(XJDC202210300486)
西北地区灾害天气延伸期预报关键技术及业务应用(YBGJXM20204A-06)
&&(Zd2022-03)
甘肃省气象局气象科研项目面上项目(Ms2021-07)
出版年
2023
NETL
NSTL
万方数据