{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:40:44Z","timestamp":1760233244789,"version":"build-2065373602"},"reference-count":51,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,21]],"date-time":"2022-12-21T00:00:00Z","timestamp":1671580800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["42201027","42192581","2019QZKK0603","2019QZKK0906"],"award-info":[{"award-number":["42201027","42192581","2019QZKK0603","2019QZKK0906"]}]},{"name":"Second Tibetan Plateau Scientific Expedition and Research","award":["42201027","42192581","2019QZKK0603","2019QZKK0906"],"award-info":[{"award-number":["42201027","42192581","2019QZKK0603","2019QZKK0906"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>It is important to develop or validate remote sensing methods to explore agricultural management and food self-sufficiency in the agricultural areas of the Qinghai\u2013Tibet Plateau under the influence of global change, ecological protection, and socio-economic development. Studies on the use of remote sensing to monitor crop planting on the Qinghai-Tibetan Plateau are limited, with inconclusive results. Therefore, in this study, we analyzed Sentinel-2A\/B images and field survey data in Hualong, China (located in Hehuang Valley, Qinghai-Tibetan Plateau) for winter wheat identification and verification at different spatial scales based on the time series of the normalized difference phenology index (NDPI) and dynamic time warping (DTW) algorithm. The characteristic phenological period and the corresponding DTW threshold were optimized using remote sensing data extracted for winter wheat. The results showed that NDPI corresponding to the jointing-heading stage, grouting-harvesting stage, and jointing-harvesting stage with DTW could identify winter wheat regardless of whether the spatial scale was a single quadrat, a combination of two quadrats, or the entire study area. The NDPI corresponding to the jointing-heading stage (corresponding DTW threshold T = 0.158) could generate a relatively rational winter wheat map; the NDPI corresponding to the time series of the grouting-harvesting stage (combined with DTW threshold T = 0.195) could detect a planting area with relatively high accuracy when supported by cultivated land, which matches the statistical reporting of the winter wheat area data. Similarly, with the support of cultivated land data, the planted area could be identified early based on the phenological characteristics of winter wheat before overwintering; however, the extraction scheme needs to be optimized further.<\/jats:p>","DOI":"10.3390\/rs15010028","type":"journal-article","created":{"date-parts":[[2022,12,22]],"date-time":"2022-12-22T02:06:14Z","timestamp":1671674774000},"page":"28","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Optimization of Characteristic Phenological Periods for Winter Wheat Extraction Using Remote Sensing in Plateau Valley Agricultural Areas in Hualong, China"],"prefix":"10.3390","volume":"15","author":[{"given":"Shenghui","family":"Lv","sequence":"first","affiliation":[{"name":"Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining 810016, China"},{"name":"State Key Laboratory of Remote Sensing Science, Beijing Normal University, Beijing 100875, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4441-9674","authenticated-orcid":false,"given":"Xingsheng","family":"Xia","sequence":"additional","affiliation":[{"name":"Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining 810016, China"},{"name":"School of Geographical Sciences, Qinghai Normal University, Xining 810016, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2307-2715","authenticated-orcid":false,"given":"Yaozhong","family":"Pan","sequence":"additional","affiliation":[{"name":"Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining 810016, China"},{"name":"State Key Laboratory of Remote Sensing Science, Beijing Normal University, Beijing 100875, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,21]]},"reference":[{"key":"ref_1","first-page":"275","article-title":"Extraction of winter wheat information based on time-series NDVl in Guanzhong area","volume":"38","author":"Guo","year":"2020","journal-title":"J. Agric. Res. Arid Areas"},{"key":"ref_2","first-page":"938","article-title":"Crop planting area extraction based on Google Earth Engine and NDVI time series difference Index","volume":"23","author":"Jiang","year":"2021","journal-title":"J. Geo-Inf. Sci."},{"key":"ref_3","first-page":"1900","article-title":"Recent progresses in research of crop patterns mapping by using remote sensing","volume":"48","author":"Hu","year":"2015","journal-title":"J. Sci. Agric. Sin."},{"key":"ref_4","first-page":"193","article-title":"Spatial extraction of winter wheat in Hebei in growing season using pixel-wise phenological curve","volume":"36","author":"Zhang","year":"2020","journal-title":"J. Trans. Chin. Soc. Agric. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/0924-2716(91)90052-W","article-title":"Use of multitemporal information to improve classification performance of TM scenes in complex terrain","volume":"46","author":"Conese","year":"1991","journal-title":"J. ISPRS J. Photogramm. Remote Sens."},{"key":"ref_6","first-page":"73","article-title":"An improved method of winter wheat remote sensing recognition based on time series","volume":"47","author":"Li","year":"2022","journal-title":"J. Sci. Surv. Mapp."},{"key":"ref_7","first-page":"578","article-title":"Crop area estimation based on MODIS-EVI time series according to distinct characteristics of key phenology phases: A case study of winter wheat area estimation in small-scale area","volume":"15","author":"Pan","year":"2011","journal-title":"J. Remote Sens."},{"key":"ref_8","first-page":"221","article-title":"Vegetation classification based on high-resolution satellite image","volume":"11","author":"Chen","year":"2007","journal-title":"J. Remote Sens."},{"key":"ref_9","first-page":"7785","article-title":"Spatio-temporal characteristics of key phenology of winter wheat in Shandong Province from 2003 to 2019","volume":"41","author":"Zhao","year":"2021","journal-title":"Acta Ecol. Sin."},{"key":"ref_10","first-page":"126","article-title":"Simulation of spatial and temporal variability of winter wheat phenology and analysis of its climate drivers based on an improved pDSSAT model","volume":"52","author":"Luo","year":"2022","journal-title":"Sci. Sin. (Terrae)"},{"key":"ref_11","first-page":"888","article-title":"Spatiotemporal differentiation of changes in wheat phenology in China under climate change from 1981 to 2010","volume":"48","author":"Liu","year":"2018","journal-title":"Sci. Sin. (Terrae)"},{"key":"ref_12","first-page":"287","article-title":"Study on spatial-temporal multiscale adaptive method of gesture recognition","volume":"44","author":"Wang","year":"2017","journal-title":"Comput. Sci."},{"key":"ref_13","first-page":"12814","article-title":"Correlation based dynamic time warping of multivariate time series","volume":"17","author":"Abonyi","year":"2012","journal-title":"Expert Syst. Appl."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3081","DOI":"10.1109\/TGRS.2011.2179050","article-title":"Satellite image time series analysis under time warping","volume":"50","author":"Petitjean","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","first-page":"267","article-title":"Extraction of paddy rice area using a DTW distance based similarity measure","volume":"36","author":"Guan","year":"2014","journal-title":"Resour. Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1109\/TASSP.1978.1163055","article-title":"Dynamic programming algorithm optimization for spoken word recognition","volume":"26","author":"Sakoe","year":"1978","journal-title":"IEEE Trans. Acoust. Speech Signal Process."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1007\/s10115-015-0885-9","article-title":"Phoneme sequence recognition via DTW-based classification","volume":"48","author":"Hamooni","year":"2016","journal-title":"Knowl. Inf. Syst."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.18637\/jss.v088.i05","article-title":"dtwsat: Time-weighted dynamic time warping for satellite image time series analysis in R","volume":"88","author":"Maus","year":"2019","journal-title":"J. Stat. Softw."},{"key":"ref_19","first-page":"673","article-title":"Spatial patterns and their changes of grain production, grain consumption and grain security in the Tibetan Plateau","volume":"34","author":"Duan","year":"2019","journal-title":"J. Nat. Res."},{"key":"ref_20","first-page":"113","article-title":"Population-Economic-Grain Regional Difference and Spatial Pattern of Qinghai Province in the Past 30 Years","volume":"42","author":"Liu","year":"2021","journal-title":"Northwest Popul. J."},{"key":"ref_21","first-page":"223","article-title":"The response of grain crops in Hehuang Valley to the climate change nearly 20 years","volume":"36","author":"Chen","year":"2018","journal-title":"Agric. Res. Arid Areas"},{"key":"ref_22","first-page":"114","article-title":"Contribution of climate change to food yield in Yellow River-Huangshui River Valley","volume":"57","author":"Chen","year":"2018","journal-title":"Hubei Agric. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Huang, F., Xia, X., Huang, Y., Lv, S., Chen, Q., Pan, Y., and Zhu, X. (2022). Comparison of winter wheat extraction methods based on different time series of vegetation indices in the Northeastern margin of the Qinghai\u2013Tibet Plateau: A case study of Minhe, China. Remote Sens., 14.","DOI":"10.3390\/rs14020343"},{"key":"ref_24","first-page":"159","article-title":"Monitoring of growth changes of winter wheat based on change vector analysis","volume":"24","author":"Gu","year":"2008","journal-title":"Trans. CSAE"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1080\/01431160010014756","article-title":"Small area estimation of crop yield using remote sensing satellite data","volume":"23","author":"Singh","year":"2002","journal-title":"Int. J. Remote Sens."},{"key":"ref_26","unstructured":"(2021, May 02). Hualong County People\u2019s Government Official Website, (In Chinese)."},{"key":"ref_27","first-page":"60","article-title":"Discussion on the conditions and control technology of yellow dwarf disease of wheat in Hualong County","volume":"4","author":"Jin","year":"1999","journal-title":"Qinghai Agro-Technol. Ext."},{"key":"ref_28","unstructured":"(2009). Hualong County becomes one of the largest winter wheat production bases in the province. Cereals Oils Process., 8, 19. (In Chinese)."},{"key":"ref_29","unstructured":"(2022, December 15). The Harvested Crop Area in Hualong Reaches 166,000 mu, (In Chinese)."},{"key":"ref_30","unstructured":"(2022, December 15). Hualong County Had a Good Harvest of Winter Wheat, (In Chinese)."},{"key":"ref_31","unstructured":"(2022, December 15). Hualong: Thousands of Hectares of Winter Wheat Green Yellow River Valley. (In Chinese)."},{"key":"ref_32","unstructured":"(2022, December 15). Winter Wheat is Growing Well in Hualong County. (In Chinese)."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Tian, Y., Jia, M., Wang, Z., Mao, D., Du, B., and Wang, C. (2020). Monitoring invasion process of Spartina alterniflora by seasonal Sentinel-2 imagery and an object-based random forest classification. Remote Sens., 12.","DOI":"10.3390\/rs12091383"},{"key":"ref_34","first-page":"83","article-title":"Crop classification based on Sentinel 2A\/B time series data in Heilonggang river basin","volume":"37","author":"Song","year":"2021","journal-title":"Jiangsu J. Agric. Sci."},{"key":"ref_35","unstructured":"(2021, May 02). The National Catalogue Service for Geographic Information. (In Chinese)."},{"key":"ref_36","first-page":"304","article-title":"Review of influencing factors of accuracy of plant phenology monitoring based on remote sensing data","volume":"35","author":"Fan","year":"2016","journal-title":"Prog. Geogr."},{"key":"ref_37","first-page":"75","article-title":"Research on vegetation indices based on the remote sensing images","volume":"24","author":"Luo","year":"2005","journal-title":"Ecol. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Dong, Q., Chen, X., Chen, J., Zhang, C., Liu, L., Cao, X., Zang, Y., Zhu, X., and Cui, X. (2020). Mapping winter wheat in North China using Sentinel 2A\/B data: A method based on phenology-time weighted dynamic time warping. Remote Sens., 12.","DOI":"10.3390\/rs12081274"},{"key":"ref_39","first-page":"1567","article-title":"Analysis on the application of time series image in extraction of winter wheat planting area","volume":"51","author":"Shi","year":"2021","journal-title":"Radio Eng."},{"key":"ref_40","first-page":"127","article-title":"Effects of NDVI time series similarity on the mapping accuracy controlled by the total planting area of winter wheat","volume":"37","author":"Li","year":"2021","journal-title":"Trans. CSAE"},{"key":"ref_41","first-page":"33","article-title":"A Comparison Between the Algorithms for Removing Cloud Pixel from MODIS NDVI Time Series Data","volume":"1","author":"Liang","year":"2011","journal-title":"Remote Sens. Nat. Resour."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3427","DOI":"10.1080\/0143116021000021251","article-title":"Evaluation of compositing algorithms over the Brazilian Amazon using SPOT-4 VEGETATION data","volume":"24","author":"Carreiras","year":"2003","journal-title":"Int. J. Remote Sens."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1585","DOI":"10.1080\/01431169208904212","article-title":"The Best Index Slope Extraction (BISE): A method for reducing noise in NDVI time-series","volume":"13","author":"Viovy","year":"1992","journal-title":"Int. J. Remote Sens."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"2649","DOI":"10.1080\/01431160116874","article-title":"Filtering pathfinder AVHRR land NDVI data for Australia","volume":"22","author":"Lovell","year":"2001","journal-title":"Int. J. Remote Sens."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.1021\/ac60214a047","article-title":"Smoothing and differentiation of data by simplified least squares procedures","volume":"36","author":"Savitzky","year":"1964","journal-title":"Anal. Chem."},{"key":"ref_46","first-page":"596","article-title":"Reconstruction of temporal NDVI dataset: Evaluation and case study","volume":"24","author":"Li","year":"2009","journal-title":"Remote Sens. Technol. Appl."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"332","DOI":"10.1016\/j.rse.2004.03.014","article-title":"A simple method for reconstructing a high-quality NDVI time-series data set based on the Savitzky\u2013Golay filter","volume":"91","author":"Chen","year":"2004","journal-title":"Remote Sens. Environ."},{"key":"ref_48","first-page":"133","article-title":"Spatiotemporal analyses of vegetation coverage variation and its responses to slope in Middle East of Gansu Province","volume":"34","author":"Zhao","year":"2019","journal-title":"Remote Sens. Inf."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"3081","DOI":"10.5194\/essd-12-3081-2020","article-title":"Early-season mapping of winter wheat in China based on Landsat and Sentinel images","volume":"12","author":"Dong","year":"2020","journal-title":"Earth Syst. Sci. Data"},{"key":"ref_50","first-page":"90","article-title":"Query tree feature extraction based on data mining for detecting SQL injection attack","volume":"42","author":"Zhang","year":"2016","journal-title":"Appl. Electron. Tech."},{"key":"ref_51","unstructured":"Zhu, W., Zeng, N., and Wang, N. (2010, January 14\u201317). Sensitivity, specificity, accuracy, associated confidence interval and ROC analysis with practical SAS implementations. Proceedings of the NESUG 2010: Health Care and Life Sciences, Baltimore, MA, USA."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/1\/28\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:47:01Z","timestamp":1760147221000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/1\/28"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,21]]},"references-count":51,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["rs15010028"],"URL":"https:\/\/doi.org\/10.3390\/rs15010028","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2022,12,21]]}}}