{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:41:17Z","timestamp":1760190077975,"version":"build-2065373602"},"reference-count":50,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2019,6,17]],"date-time":"2019-06-17T00:00:00Z","timestamp":1560729600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["No.41871231"],"award-info":[{"award-number":["No.41871231"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2016YFB0501502"],"award-info":[{"award-number":["2016YFB0501502"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>High temporal resolution remote sensing satellite data can be used to collect vegetation phenology observations over regional and global scales. Logistic and polynomial functions are the most widely used methods for fitting time series normalized difference vegetation index (NDVI) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). Furthermore, the maximum in the curvature of the fitted curve is usually considered as the spring green-up date. However, the existing green-up date calculation methods have low accuracy for sparse vegetation. This paper proposes an improved green-up date calculation method using a coupled model and anomalous point detection (CMAPD). This model is based on a combination of logistic and polynomial functions, which is used to fit time series vegetation index. Anomalous values were identified using the nearest neighbor algorithm, and these values were corrected by the combination of growing degree-days (GDD) and land use type. Then, the trends and spatial patterns of green-up date was analyzed in the Sanjiangyuan area. The results show that the coupled model fit the time series data better than a single logistic or polynomial function. Besides, the anomalous point detection method properly controlled the green-up date within the local threshold, and could reflect green-up date more accurately. In addition, a weak statistically significant advance trend for average vegetation green-up date was observed from 2000 to 2016. However, in 10.4% of the study area, the the green-up date has significant advanced. Regression analysis showed that the green-up date is correlated to elevation: the green-up date is clearly later at higher elevations.<\/jats:p>","DOI":"10.3390\/rs11121432","type":"journal-article","created":{"date-parts":[[2019,6,17]],"date-time":"2019-06-17T03:24:41Z","timestamp":1560741881000},"page":"1432","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Improved Spring Vegetation Phenology Calculation Method Using a Coupled Model and Anomalous Point Detection"],"prefix":"10.3390","volume":"11","author":[{"given":"Qian","family":"Luo","sequence":"first","affiliation":[{"name":"State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China"},{"name":"Beijing Engineering Research Center for Global Land Remote Sensing Products, Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jinling","family":"Song","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China"},{"name":"Beijing Engineering Research Center for Global Land Remote Sensing Products, Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lei","family":"Yang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China"},{"name":"Beijing Engineering Research Center for Global Land Remote Sensing Products, Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4962-4888","authenticated-orcid":false,"given":"Jindi","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China"},{"name":"Beijing Engineering Research Center for Global Land Remote Sensing Products, Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,6,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/j.biocon.2013.06.024","article-title":"Human-snow leopard conflicts in the Sanjiangyuan Region of the Tibetan Plateau","volume":"166","author":"Li","year":"2013","journal-title":"Biol. Conserv."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.agrformet.2014.01.003","article-title":"Increasing altitudinal gradient of spring vegetation phenology during the last decade on the Qinghai\u2013Tibetan Plateau","volume":"189","author":"Shen","year":"2014","journal-title":"Agric. For. Meteorol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2365","DOI":"10.1890\/11-1408.1","article-title":"Effects of warming and grazing on soil N availability, species composition, and ANPP in an alpine meadow","volume":"93","author":"Wang","year":"2012","journal-title":"Ecology"},{"key":"ref_4","first-page":"528","article-title":"High positive correlation between soil temperature and NDVI from 1982 to 2006 in alpine meadow of the Three-River Source Region on the Qinghai-Tibetan Plateau","volume":"13","author":"Xu","year":"2011","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"792","DOI":"10.1016\/j.agrformet.2011.01.009","article-title":"Response of ecosystem respiration to warming and grazing during the growing seasons in the alpine meadow on the Tibetan plateau","volume":"151","author":"Lin","year":"2011","journal-title":"Agric. For. Meteorol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.ecoleng.2016.05.011","article-title":"Ecosystem change assessment in the Three-river Headwater Region, China: Patterns, causes, and implications","volume":"93","author":"Chong","year":"2016","journal-title":"Ecol. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ecoleng.2014.12.007","article-title":"Ecological and hydrological responses to changing environmental conditions in China\u2019s river basins","volume":"76","author":"Yang","year":"2015","journal-title":"Ecol. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"12057","DOI":"10.3390\/ijerph121012057","article-title":"Climate change and its impact on the eco-environment of the Three-Rivers Headwater Region on the Tibetan Plateau, China","volume":"12","author":"Jiang","year":"2015","journal-title":"Int. J. Environ. Res. Public Health"},{"key":"ref_9","first-page":"1645","article-title":"Integrated assessment on the effectiveness of ecological conservation in Sanjiangyuan National Nature Reserve","volume":"32","author":"Shao","year":"2013","journal-title":"Geogr. Res."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Tan, K., Ciais, P., Piao, S., Wu, X., Tang, Y., Vuichard, N., Liang, S., and Fang, J. (2010). Application of the ORCHIDEE global vegetation model to evaluate biomass and soil carbon stocks of Qinghai-Tibetan grasslands. Glob. Biogeochem. Cycles, 24.","DOI":"10.1029\/2009GB003530"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1170","DOI":"10.1111\/j.1461-0248.2004.00677.x","article-title":"Experimental warming causes large and rapid species loss, dampened by simulated grazing, on the Tibetan Plateau","volume":"7","author":"Klein","year":"2004","journal-title":"Ecol. Lett."},{"key":"ref_12","first-page":"E2854","article-title":"Declining snow cover may affect spring phenological trend on the Tibetan Plateau","volume":"110","author":"Wang","year":"2013","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"663","DOI":"10.1038\/nclimate1580","article-title":"Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings","volume":"2","author":"Yao","year":"2012","journal-title":"Nat. Clim. Chang."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"811","DOI":"10.1093\/treephys\/18.12.811","article-title":"Effects of photoperiod and temperature on the timing of bud burst in Norway spruce (Picea abies)","volume":"18","author":"Partanen","year":"1998","journal-title":"Tree Physiol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"672","DOI":"10.1111\/j.1365-2486.2006.01123.x","article-title":"Variations in satellite-derived phenology in China\u2019s temperate vegetation","volume":"12","author":"Piao","year":"2006","journal-title":"Glob. Chang. Biol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1016\/S0034-4257(02)00135-9","article-title":"Monitoring vegetation phenology using MODIS","volume":"84","author":"Zhang","year":"2003","journal-title":"Remote Sens. Environ."},{"key":"ref_17","first-page":"1117","article-title":"Identifying an optimal method for estimating greenup date of Kobresia pygmaea alpine meadow in Qinghai-Tibetan Plateau","volume":"18","author":"Fan","year":"2014","journal-title":"J. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1029\/97GB00330","article-title":"A continental phenology model for monitoring vegetation responses to interannual climatic variability","volume":"11","author":"White","year":"1997","journal-title":"Glob. Biogeochem. Cycles"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"566","DOI":"10.1007\/s13280-012-0366-2","article-title":"Managing the three-rivers headwater region, China: From Ecol. Eng. to social engineering","volume":"42","author":"Fang","year":"2013","journal-title":"Ambio"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1007\/s11119-015-9412-y","article-title":"Improving in-season estimation of rice yield potential and responsiveness to topdressing nitrogen application with Crop Circle active crop canopy sensor","volume":"17","author":"Cao","year":"2016","journal-title":"Precis. Agric."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"22151","DOI":"10.1073\/pnas.1012490107","article-title":"Winter and spring warming result in delayed spring phenology on the Tibetan Plateau","volume":"107","author":"Yu","year":"2010","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2335","DOI":"10.1111\/j.1365-2486.2009.01910.x","article-title":"Intercomparison, interpretation, and assessment of spring phenology in North America estimated from Remote Sensing for 1982\u20132006","volume":"15","author":"White","year":"2009","journal-title":"Glob. Chang. Biol."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Ren, Q., He, C., Huang, Q., and Zhou, Y. (2018). Urbanization Impacts on Vegetation Phenology in China. Remote Sens., 10.","DOI":"10.3390\/rs10121905"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Xia, C., Li, J., and Liu, Q. (2012, January 22\u201327). Monitoring vegetation phenology in China using time-series MODIS LAI data. Proceedings of the 2012 IEEE International Geoscience and Remote Sensing Symposium, Munich, Germany.","DOI":"10.1109\/IGARSS.2012.6350912"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1404","DOI":"10.1109\/JSTARS.2015.2398427","article-title":"MODIS NBAR time series modeling with two statistical methods and application to leaf area index recursive estimation","volume":"8","author":"Tian","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"McGregor, G.R. (2016). Climate variability and change in the Sanjiangyuan region. Landscape and Ecosystem Diversity, Dynamics and Management in the Yellow River Source Zone, Springer.","DOI":"10.1007\/978-3-319-30475-5_2"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3511","DOI":"10.3390\/rs6043511","article-title":"Mapping plant functional types over broad mountainous regions: A hierarchical soft time-space classification applied to the Tibetan Plateau","volume":"6","author":"Cai","year":"2014","journal-title":"Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Huang, S., Miao, Y., Yuan, F., Gnyp, M., Yao, Y., Cao, Q., Wang, H., Lenz-Wiedemann, V., and Bareth, G. (2017). Potential of RapidEye and WorldView-2 satellite data for improving rice nitrogen status monitoring at different growth stages. Remote Sens., 9.","DOI":"10.3390\/rs9030227"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1002\/joc.1236","article-title":"Application of nearest-neighbor resampling for homogenizing temperature records on a daily to sub-daily level","volume":"26","author":"Brandsma","year":"2006","journal-title":"Int. J. Climatol. J. R. Meteorol. Soc."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1080\/01431160010006449","article-title":"Using satellite Remote Sensing for DEM extraction in complex mountainous terrain: Landscape analysis of the Makalu Barun National Park of eastern Nepal","volume":"23","author":"Zomer","year":"2002","journal-title":"Int. J. Remote Sens."},{"key":"ref_31","first-page":"3","article-title":"A study on effects of spectral response function and band width on land surface temperature inversion","volume":"5","author":"Liu","year":"2007","journal-title":"Remote Sens. Inf."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1080\/02693799008941549","article-title":"Kriging: A method of interpolation for geographical information systems","volume":"4","author":"Oliver","year":"1990","journal-title":"Int. J. Geogr. Inf. Syst."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1007\/s10584-012-0434-4","article-title":"Specification of thermal growing season in temperate China from 1960 to 2009","volume":"114","author":"Shen","year":"2012","journal-title":"Clim. Chang."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1111\/j.1466-8238.2011.00675.x","article-title":"Extension of the growing season due to delayed autumn over mid and high latitudes in North America during 1982\u20132006","volume":"21","author":"Zhu","year":"2012","journal-title":"Glob. Ecol. Biogeogr."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1016\/j.rse.2018.04.030","article-title":"The mixed pixel effect in land surface phenology: A simulation study","volume":"211","author":"Chen","year":"2018","journal-title":"Remote Sens. Environ."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"8564","DOI":"10.1103\/PhysRevB.62.8564","article-title":"Second nearest-neighbor modified embedded-atom-method potential","volume":"62","author":"Lee","year":"2000","journal-title":"Phys. Rev. B"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1016\/j.ecolind.2014.11.004","article-title":"Temperature sensitivity of spring vegetation phenology correlates to within-spring warming speed over the Northern Hemisphere","volume":"50","author":"Wang","year":"2015","journal-title":"Ecol. Indic."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1111\/gcb.13081","article-title":"Temperature, precipitation, and insolation effects on autumn vegetation phenology in temperate China","volume":"22","author":"Liu","year":"2016","journal-title":"Glob. Chang. Biol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"7320","DOI":"10.3390\/rs6087320","article-title":"Global-scale associations of vegetation phenology with rainfall and temperature at a high spatio-temporal resolution","volume":"6","author":"Clinton","year":"2014","journal-title":"Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"013511","DOI":"10.1117\/1.2740040","article-title":"Spatial mapping of growing degree days: An application of MODIS-based surface temperatures and enhanced vegetation index","volume":"1","author":"Hassan","year":"2007","journal-title":"J. Appl. Remote Sens."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1093\/jpe\/rts010","article-title":"Applicability of Remote Sensing-based surface temperature regimes in determining deciduous phenology over boreal forest","volume":"6","author":"Hassan","year":"2012","journal-title":"J. Plant Ecol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"785","DOI":"10.2307\/1931815","article-title":"A critique of the heat unit approach to plant response studies","volume":"41","author":"Wang","year":"1960","journal-title":"Ecology"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2402","DOI":"10.1002\/joc.3590","article-title":"Thermal growing season trends in east China, with emphasis on urbanization effects","volume":"33","author":"Yang","year":"2013","journal-title":"Int. J. Climatol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1781","DOI":"10.1002\/joc.823","article-title":"Relationships among phenological growing season, time-integrated normalized difference vegetation index and climate forcing in the temperate region of eastern China","volume":"22","author":"Chen","year":"2002","journal-title":"Int. J. Climatol. A J. R. Meteorol. Soc."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1016\/S0022-1694(01)00594-7","article-title":"Power of the Mann\u2013Kendall and Spearman\u2019s rho tests for detecting monotonic trends in hydrological series","volume":"259","author":"Yue","year":"2002","journal-title":"J. Hydrol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2106","DOI":"10.1109\/TPAMI.2010.128","article-title":"Linear regression for face recognition","volume":"32","author":"Naseem","year":"2010","journal-title":"IEEE Transact. Pattern Anal. Mach. Intell."},{"key":"ref_47","first-page":"5495","article-title":"Response of vegetation to climate change and human activity based on NDVI in the Three-River Headwaters region","volume":"31","author":"Li","year":"2011","journal-title":"Shengtai Xuebao\/Acta Ecol. Sin."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1599","DOI":"10.1016\/j.agrformet.2011.06.016","article-title":"Altitude and temperature dependence of change in the spring vegetation green-up date from 1982 to 2006 in the Qinghai-Xizang Plateau","volume":"151","author":"Piao","year":"2011","journal-title":"Agric. For. Meteorol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1175\/1520-0477(2001)082<0399:CITOOS>2.3.CO;2","article-title":"Changes in the onset of spring in the western United States","volume":"82","author":"Cayan","year":"2001","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.agrformet.2014.09.003","article-title":"Estimation of crop gross primary production (GPP): II. Do scaled MODIS vegetation indices improve performance?","volume":"200","author":"Zhang","year":"2015","journal-title":"Agric. For. Meteorol."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/12\/1432\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:58:56Z","timestamp":1760187536000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/12\/1432"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,6,17]]},"references-count":50,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2019,6]]}},"alternative-id":["rs11121432"],"URL":"https:\/\/doi.org\/10.3390\/rs11121432","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2019,6,17]]}}}