Remote sensing estimation of vegetation cover in alpine grassland in the growing and non-growing seasons

doi:10.11686/cyxb2020324

Abstract

Abstract:

Vegetation cover is an important ecological parameter for describing vegetation status of terrestrial ecosystems. Using Landsat-8OLI data for Dangxiong County as the data source， the most suitable vegetation index for estimation of vegetation cover in Alpine Grassland in the growing and non-growing seasons was selected from 10 commonly used vegetation indices. A three-pixel linear mixed model was used to estimate the end element values. The optimal vegetation index for inversion of vegetation cover in the growing and non-growing seasons was determined by comparison of results obtained using the different vegetation indices， based on the pixel bisection model. The selected model was then used to analyze the temporal and spatial distribution of vegetation cover in the growing and non-growing seasons. The results showed that： 1） A vegetation index constructed from the visible-near infrared band performed best for the inversion of vegetation cover in the growing season， and an index constructed from the shortwave infrared was suitable for the inversion of vegetation cover in the non-growing season. 2） The modified soil-adjusted corn residue index （MSACRI） pixel dichotomy model was the best model to invert the vegetation cover in the non-growing season， and the normalized difference vegetation index （NDVI） pixel dichotomy model was the best for inversion of the vegetation cover in the growing season. 3） Across a gradient of increasing altitude， the vegetation cover presented a single-peak pattern with the peak at mid-altitude. Grassland was mainly found at 4300-5100 m above sea level. The vegetation cover in the growing season typically ranged from 20% to 80%， while cover in the non-growing season was mostly less than 40%. This research results provides reference data for studies on grassland ecosystem carbon storage， vegetation productivity， soil erosion， and ecological hydrology.

Key words: growing season, non-growing season, vegetation cover, vegetation index, alpine grassland

Jia-li LIU, Jian-rong FAN, Xi-yu ZHANG, Chao YANG, Fu-bao XU, Xiao-xue ZHANG, Bo LIANG. Remote sensing estimation of vegetation cover in alpine grassland in the growing and non-growing seasons[J]. Acta Prataculturae Sinica, 2021, 30(9): 15-26.

Figures/Tables 9

Fig.1 Distribution of sample plots in Dangxiong County

Table 1 Several main vegetation indices for grassland coverage estimation

植被指数 Vegetation index	计算公式 Calculation formula
RVI	$N I R / R$
NDVI	$(N I R - R) / (N I R + R)$
SAVI	$[(N I R - R) / (N I R + R + L)] (1 + L)$
TSAVI	$[a (N I R - a R - b) / (R + a N I R - a b)]$
MSAVI	$[2 N I R + 1 - (2 N I R + 1) 2 - 8 (N I R - R)] 2$
NDTI	$S W I R 1 - S E I R 2 S W I R 1 + S W I R 2$
MSACRI	$C × α (S W I R 1 - a S W I R 2 - β) α S W I R 1 + S W I R 2 - α β α β$
DFI	$100 × (1 - S W I R 2 S W I R 1) R E D N I R$
STI	$S W I R 1 S W I R 2$
S-NDTI	$(1 + L) S W I R 1 - S W I R 2 S W I R 1 + S W I R 2 + L$

Table 1 Several main vegetation indices for grassland coverage estimation

植被指数 Vegetation index	计算公式 Calculation formula
RVI	$N I R / R$
NDVI	$(N I R - R) / (N I R + R)$
SAVI	$[(N I R - R) / (N I R + R + L)] (1 + L)$
TSAVI	$[a (N I R - a R - b) / (R + a N I R - a b)]$
MSAVI	$[2 N I R + 1 - (2 N I R + 1) 2 - 8 (N I R - R)] 2$
NDTI	$S W I R 1 - S E I R 2 S W I R 1 + S W I R 2$
MSACRI	$C × α (S W I R 1 - a S W I R 2 - β) α S W I R 1 + S W I R 2 - α β α β$
DFI	$100 × (1 - S W I R 2 S W I R 1) R E D N I R$
STI	$S W I R 1 S W I R 2$
S-NDTI	$(1 + L) S W I R 1 - S W I R 2 S W I R 1 + S W I R 2 + L$

Fig.2 Soil line

Fig.3 Tri-endmember linear mixture model with the NDVI and DFI

Table 2 Correlation between grassland coverage and vegetation index

植被指数 Vegetation index	4月相关系数 April correlation coefficient	8月相关系数 August correlation coefficient	适用性 Applicability
NDVI	0.73**	0.88**	适用于生长季Suitable for growing season
RVI	0.77**	0.85**
SAVI	0.73**	0.88**
TSAVI	0.73**	0.88**
MSAVI	0.71**	0.88**
NDTI	0.92**	0.80**	适用于非生长季Suitable for non-growing season
MSACRI	0.92**	0.80**
S-NDTI	0.92**	0.80**
DFI	0.90**	-0.28
STI	0.92**	0.78**

Fig.4 Distribution of alpine grassland coverage in growing season/non-growing season in Dangxiong County

Table 3 The accuracy evaluation of grassland coverage based on dimidiate pixel model

非生长季/生长季 Non-growing season/growing season	植被指数 Vegetation index	平均相对误差 Average relative error （%）	均方根误差RMSE	R²
非生长季Non-growing season	MSACRI	10.18	7.78	0.81**
	S-NDTI	10.13	9.86	0.70**
	NDTI	20.09	9.47	0.72**
	STI	29.96	9.38	0.73**
	DFI	44.02	9.08	0.74**
生长季Growing season	NDVI	9.23	8.43	0.77**
	TSAVI	11.20	11.73	0.55**
	MSAVI	13.70	11.41	0.58**
	SAVI	22.64	11.96	0.54**
	RVI	21.96	12.05	0.53**

Fig.5 Statistics of vegetation coverage area in different altitude growing seasons

Fig.6 Statistics of vegetation coverage area in different altitude non-growing seasons

References 39

1	Sun H L， Zheng D， Yao T D， et al. Protection and construction of the national ecological security shelter zone on Tibetan Plateau. Acta Geographica Sinica， 2012， 67（1）： 3-12.
	孙鸿烈，郑度，姚檀栋，等. 青藏高原国家生态安全屏障保护与建设. 地理学报， 2012， 67（1）： 3-12.
2	Wen Q K， Zhang Z X， Liu B， et al. Research progress in grassland fractional coverage estimation methods. Pratacultural Science， 2009， 26（12）： 30-36.
	温庆可，张增祥，刘斌，等. 草地覆盖度测算方法研究进展. 草业科学， 2009， 26（12）： 30-36.
3	Guerschman J P， Hill M J， Renzullo L J， et al. Estimating fractional cover of photosynthetic vegetation， non-photosynthetic vegetation and bare soil in the Australian tropical savanna region upscaling the EO-1 Hyperion and MODIS sensors. Remote Sensing of Environment， 2009， 113（5）： 928-945.
4	Ding M J， Zhang Y L， Liu L S， et al. Temporal and spatial distribution of grassland coverage change in Tibetan Plateau since 1982. Journal of Natural Resources， 2010， 25（12）： 2114-2122.
	丁明军，张镱锂，刘林山，等. 1982-2009年青藏高原草地覆盖度时空变化特征. 自然资源学报， 2010， 25（12）： 2114-2122.
5	Chai G Q， Wang J P， Zou X Y， et al. Estimation fractional cover of photosynthetic/non-photosynthetic vegetation in a typical steppe region based on sentinel-2 data. Pratacultural Science， 2018， 35（12）： 2836-2844.
	柴国奇，王静璞，邹学勇，等. 基于Sentinel-2数据的典型草原光合/非光合植被覆盖度估算. 草业科学， 2018， 35（12）： 2836-2844.
6	Zhou D W， Sun H X， Zhong R Z， et al. Principles and practice of grassland farming. Acta Agrestia Sinica， 2016， 24（4）： 718-725.
	周道玮，孙海霞，钟荣珍，等. 草地畜牧理论与实践. 草地学报， 2016， 24（4）： 718-725.
7	Guo Q， Hu Z M， Li X R， et al. Effects of precipitation timing on aboveground net primary productivity in Inner Mongolia temperate steppe. Acta Ecologica Sinica， 2013， 33（15）： 4808-4817.
	郭群，胡中民，李轩然，等. 降水时间对内蒙古温带草原地上净初级生产力的影响. 生态学报， 2013， 33（15）： 4808-4817.
8	Arsenault É， Bonn F. Evaluation of soil erosion protective cover by crop residues using vegetation indices and spectral mixture analysis of multispectral and hyperspectral data. Catena， 2005， 62（2/3）： 157-172.
9	Xia Y， Fan J R， Zhang X Y， et al. Application of composite vegetation index in remote sensing inversion of sparse fractional vegetation cover in alpine steppe. Pratacultural Science， 2017， 34（9）： 1767-1777.
	夏颖，范建容，张茜彧，等. 复合植被指数在稀疏高寒草原植被盖度遥感反演中的应用. 草业科学， 2017， 34（9）： 1767-1777.
10	You H Y， Luo C F， Liu Z J， et al. Estimation vegetation coverage based on vegetation index of MODIS data in Qinghai Lake watershed. Remote Sensing Information， 2017， 27（5）： 55-60.
	游浩妍，骆成凤，刘正军，等. 基于MODIS植被指数估算青海湖流域植被覆盖度研究. 遥感信息， 2017， 27（5）： 55-60.
11	Li C Y， Fan W T， Li G M， et al. Drive force analysis of changes in grassland coverage on the Qinghai-Tibet Plateau based on NDVI in 2000-2016. Acta Prataculturae Sinica， 2019， 28（10）： 25-32.
	李重阳，樊文涛，李国梅，等. 基于NDVI的2000-2016年青藏高原牧户草场覆盖度变化驱动力分析. 草业学报， 2019， 28（10）： 25-32.
12	Chu D， Pubu C R， Deji Y Z， et al. Aboveground biomass estimate methods of grassland in the central Tibet. Journal of Mountain Science， 2013， 31（6）： 664-671.
	除多，普布次仁，德吉央宗，等. 西藏高原中部草地地上生物量遥感估算方法. 山地学报， 2013， 31（6）： 664-671.
13	Daughtry C S T， Hunt E R， Mcmurtrey J E. Assessing crop residue cover using shortwave infrared reflectance. Remote Sensing of Environment， 2004， 90（1）： 126-134.
14	Asner G P. Biophysical and biochemical sources of variability in canopy reflectance. Remote Sensing of Environment， 1998， 64（3）： 234-253.
15	Daughtry C S T. Discriminating crop residues from soil by shortwave infrared reflectance. Agronomy Journal， 2001， 93（1）： 125.
16	Deventer V， Ward A， Gowda P H， et al. Using thematic mapper data to identify contrasting soil plains and tillage practices. Photogrammetric Engineering and Remote Sensing， 1997， 1（63）： 87-93.
17	Bannari K， Haboudane D， Mcnairn H， et al. Modified soil adjusted crop residue index （MSACRI）： A new index for mapping crop IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the pulse of the planet： The role of remote sensing in managing the environment. Proceedings （Cat. No.00CH37120）. USA： Institute of Electrical and Electronics Engineers， 2000.
18	Serbin G， Hunt E R， Daughtry C S T， et al. An improved ASTER index for remote sensing of crop residue. Remote Sensing， 2009， 1（4）： 971-991.
19	Cao X， Chen J， Matsushita B， et al. Developing a MODIS-based index to discriminate dead fuel from photosynthetic vegetation and soil background in the Asian steppe area. International Journal of Remote Sensing， 2010， 31（6）： 1589-1604.
20	Asner G P， Heidebrecht K B. Spectral unmixing of vegetation， soil and dry carbon cover in arid regions： Comparing multispectral and hyperspectral observations. International Journal of Remote Sensing， 2002， 23（19）： 3939-3958.
21	Daughtry C S T， Hunt E R， Doraiswamy P C， et al. Remote sensing the spatial distribution of crop residues. Agronomy Journal， 2005， 97（3）： 864.
22	Li X， Wang Z， Zhao J X， et al. Altitudinal variations in the sensitivity of alpine meadow productivity to temperature and precipitation changes along the southern slope of Nyainqentanglha Mountains. Acta Ecologica Sinica， 2017， 37（17）： 5591-5601.
	李翔，王忠，赵景学，等.念青唐古拉山南坡高寒草甸生产力对温度和降水变化的敏感性及其海拔分异. 生态学报， 2017， 37（17）： 5591-5601.
23	Yu J H， Liu X S， Luo T X， et al. Seasonal variations of soil temperature and moisture at the upper limit of alpine meadow in north-facing slope of the Nianqingtanggula Mountains. Acta Geographica Sinica， 2012， 67（9）： 1246-1254.
	俞洁辉，刘新圣，罗天祥，等. 念青唐古拉山北麓草甸海拔分布上限土壤温湿度的季节变化. 地理学报， 2012， 67（9）： 1246-1254.
24	Rouse J W， Haas R H， Schell J A， et al. Monitoring the vernal advancement and retrogradation （green wave effect） of natural vegetation. Nasa/gsfct Type Final Report， 1974： 371.
25	Jordan C F. Derivation of leaf-area index from quality of light on the forest floor. Ecology， 1969， 50（4）： 663-666.
26	Huete A R. A soil-adjusted vegetation index （SAVI）. Remote Sensing of Environment， 1988， 3（25）： 295-309.
27	Baret F， Guyot G， Major， et al. TSAVI： A vegetation index which minimizes soil brightness effects on LAI and APAR estimation： 12th Canadian symposium on remote sensing geoscience and remote sensing symposium. Canada： Institute of Electrical and Electronics Engineers， 1989.
28	Qi J， Huete A R， Moran M S， et al. Interpretation of vegetation indices derived from multi-temporal SPOT images. Remote Sensing of Environment， 1993， 44（1）： 89-101.
29	Ren H， Zhou G， Zhang F. Estimation of litter mass in nongrowing seasons in arid grasslands using MODIS satellite data. European Journal of Remote Sensing， 2018， 51（1）： 222-230.
30	Wang G Z， Wang J P， Zou X Y， et al. A review on estimation fractional cover of non-photosynthetic vegetation by using remote sensing. Remote Sensing Technology and Application， 2018， 33（1）： 1-9.
	王光镇，王静璞，邹学勇，等. 遥感技术估算非光合植被覆盖度研究综述. 遥感技术与应用， 2018， 33（1）： 1-9.
31	Qi J， Marsett R， Heilman P， et al. Ranges improves satellite-based information and land cover assessments in southwest United States. Eos Transactions of the American Geophysical Union， 2002（83）： 601-606.
32	Dai J， Roberts D， Dennison P， et al. Spectral-radiometric differentiation of non-photosynthetic vegetation and soil within Landsat and Sentinel 2 wavebands. Remote Sensing Letters， 2018， 9（8）： 733-742.
33	Asner G P， Borghi C E， Ojeda R A. Desertification in central argentina： Changes in ecosystem carbon and nitrogen from imaging spectroscopy. Ecological Applications， 2003， 13（3）： 629-648.
34	Ren W M. Study on the applicability of vegetation index calculation area vegetation coverage. Xi’an： Northwest University， 2012.
	任唯敏. 植被指数计算区域植被覆盖度的适用性研究. 西安：西北大学， 2012.
35	Zhang C. Remote sensing inversion and spatio-temporal dynamic analysis of litter coverage： A case study in the loess hilly-gully region. Xi’an： Northwest University， 2019.
	张超. 枯枝落叶层盖度遥感反演及时空变化分析. 西安：西北大学， 2019.
36	Yang J Y. Ground biomass simulation of the grassland in Hejing County of Xinjiang based on vegetation index. Urumqi： Xinjiang Normal University， 2017.
	杨静雅. 基于植被指数的新疆和静县草原地上生物量模拟. 乌鲁木齐：新疆师范大学， 2017.
37	Ge J， Meng B P， Yang S X， et al. Monitoring of above-ground biomass in alpine grassland based on agricultural digital camera and MODIS remote sensing data： A case study in the Yellow River headwater region. Acta Prataculturae Sinica， 2017， 26（7）： 23-34.
	葛静，孟宝平，杨淑霞，等. 基于ADC和MODIS遥感数据的高寒草地地上生物量监测研究——以黄河源区为例. 草业学报， 2017， 26（7）： 23-34．
38	Li M M. The method of vegetation fraction estimation by remote sensing. Beijing： Graduate School of Chinese Academy of Sciences （Research Institute of Remote Sensing Application）， 2003.
	李苗苗. 植被覆盖度的遥感估算方法研究. 北京：中国科学院研究生院（遥感应用研究所）， 2003.
39	Jin Y L， Wang Z， Zhang L. Altitudinal differentiation of alpine grassland NDVI and its indications in Dangxiong County， Tibet. Journal of Natural Resources， 2015， 30（6）： 929-937.
	金远亮，王忠，张林. 西藏当雄县高寒草地NDVI的海拔分异特征及其指示. 自然资源学报， 2015， 30（6）： 929-937.

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