مجله جنگل ایران

مجله جنگل ایران

ارزیابی تأثیر روش‌های هموارسازی بر محاسبۀ فنولوژی در جنگل‌های زاگرس با استفاده از داده‌های ماهوارۀ مودیس (مطالعۀ موردی: مریوان)

نوع مقاله : مقاله پژوهشی

نویسندگان
1 دانش‌آموختۀ کارشناسی ارشد سنجش از دور، دانشکدۀ مهندسی، دانشگاه بوعلی سینا، همدان، ایران
2 استادیار سنجش از دور، گروه مهندسی عمران، دانشکدۀ مهندسی، دانشگاه بوعلی سینا، همدان، ایران
چکیده
مقدمه: تغییر اقلیم به تغییرات عوامل آب‌و‌هوایی یک منطقه در دورۀ بلندمدت اطلاق می‌شود و تأثیر مهمی بر فرایندهای اکولوژیکی آن منطقه دارد. بررسی تغییرات فنولوژی گیاهان، اهمیت زیادی در درک رفتار اکوسیستم‌های زمین در مواجهه با تغییرات اقلیمی دارد. روش‌های سنجش از دور امکان بررسی تغییرات فنولوژی را در عرصۀ وسیع فراهم می‌کنند. هدف از این تحقیق بررسی این تغییرات با استفاده از سری زمانی حاصل از تصاویر ماهواره‌ای در بخشی از جنگل‌های زاگرس است.
 مواد و روش‌ها: مرسوم‌ترین روش سنجش از دور در محاسبۀ پارامترهای فنولوژی گیاهان، استفاده از سری زمانی شاخص‌های گیاهی است که به‌طور معمول پیوستگی روزانۀ آنها به‌دلیل پوشش ابر مخدوش شده و مقدار آنها نیز تحت تأثیر نویز قرار دارد. این مشکلات با به‌کارگیری فیلترهای هموارساز تا حدودی قابل رفع است، هرچند مشخصات فیلترها باید با دقت انتخاب شود. به‌منظور استخراج پارامترهای فنولوژیکی، از داده‌های سری زمانی شاخص پوشش گیاهی تفاضلی نرمال‌شده و شاخص پوشش گیاهی بهبودیافتۀ مستخرج از تصاویر سنجندۀ مودیس در یک دورۀ ده‌ساله (2018‌- 2009) استفاده شد. برای استخراج پارامترهای فنولوژی، از جمله شروع و پایان فصل رویش، سری‌های زمانی NDVIratio و EVIratio، با اعمال دو تابع ساویتزکی-گولای و میانگین متحرک هموارسازی شدند. برای اعتبارسنجی نتایج نیز از داده‌های زمینی که با مشاهدۀ مستقیم وضعیت درختان (با نمونه‌برداری تصادفی) در منطقه جمع‌آوری شده‌اند استفاده شد.
نتایج: به‌کارگیری تابع میانگین متحرک با اندازۀ پنجره 6 و تابع ساویتزکی-گولای با اندازۀ پنجره ۱۱ و درجۀ 2، موجب بیشترین افزایش دقت برای هر دو شاخص گیاهی شده است. پس از اعمال تابع هموارسازی بهینه، پارامتر شروع فصل، حاصل از EVIratio  برآورد دقیق‌تری  (92/0 R2 =) از نتیجۀ حاصل از NDVIratio  ارائه داده است. شروع فصل رویش در طول این ده سال به‌صورت متوسط 5/0 روز در سال کاهش یافته و پایان فصل رویش به‌صورت متوسط 3/1 روز در سال افزایش یافته است.
نتیجه‌گیری: به‌صورت کلی، در اغلب مناطق زمان شروع فصل رویش روند کاهشی و پایان فصل رویش روند افزایشی داشته‌اند. به‌عبارت دیگر، روند تعجیل در شروع فصل و تأخیر در پایان فصل، سبب افزایش طول فصل رویش در اغلب مناطق تحت بررسی شده است.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Evaluating the Impact of Smoothing Methods on Phenology Calculation in Zagros Forests using MODIS Satellite Data (Case Study: Marivan)

نویسندگان English

F. Mahdavipoor 1
H. Torabzadeh 2
M. Heidari Mozaffar 2
1 Master Graduated Remote Sensing, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran
2 Assistant Prof., of Remote Sensing, Dept. of Civil Engineering, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran
چکیده English

Introduction: Climate change refers to long-term alterations in the climatic factors of a region, significantly impacting its ecological processes. The investigation of plant phenological changes is crucial for comprehending the behavioral responses of Earth ecosystems to climate change. Remote sensing methods facilitate the examination of phenological changes over extensive areas. This research aims to explore such changes using time series data obtained from satellite images in a part of the Zagros forests.
Materials and Methods: The most common method in remote sensing for calculating plant phenology parameters involves using time series of vegetation indices, which are usually disrupted by cloud cover and affected by noise. These issues can be somewhat mitigated by employing smoothing filters although the characteristics of the filters need to be carefully chosen. To extract phenological parameters, time series data of the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) from MODIS data, over a ten-year period (From 2009 to 2018), were used. For the extraction of phenological parameters, including the start of the growing season and end of the growing season, the time series of NDVIratio and EVIratio were smoothed using two smoothing functions: Savitzky–Golay and Moving Average filters. For the validation of the results, in-situ data were collected in the area through direct observation of tree status (via random sampling).
Results: The use of the Moving Average function with a window size of six and the Savitzky–Golay function with a window size of 11 and a degree of two has led to the highest increase in accuracy for both vegetation indices. After employing the optimal smoothing function, the parameter for the start of the season, obtained from EVIratio, provided a more accurate estimate (R2 = 0.92) compared to the result from NDVIratio. Over the ten year period, the start of the season has been reduced by an average of 0.5 days per year over the ten-year period, and end of the season has been increased by an average of 1.3 days per year.
Conclusion:  Overall, in most areas, the start and end of the growing season has shown a decreasing and an increasing trend, respectively. In other words, the trend of earlier start and later end of the season has led to an increase in the length of the growing season in most of the study areas.

کلیدواژه‌ها English

Climate change
EVI
MODIS
NDVI
Phenology
Cai, Z., Jönsson, P., Jin, H., & Eklundh, L. (2017). Performance of smoothing methods for reconstructing NDVI time-series and estimating vegetation phenology from MODIS data. Remote Sensing9(12), 1271. https://doi.org/10.3390/rs9121271
Caparros-Santiago, J.A., Rodriguez-Galiano, V., & Dash, J. (2021). Land surface phenology as indicator of global terrestrial ecosystem dynamics: A systematic review. ISPRS Journal of Photogrammetry and Remote Sensing171, 330-347. https://doi.org/10.1016/j.isprsjprs.2020.11.019
Chen, X., Wang, W., Chen, J., Zhu, X., Shen, M., Gan, L., & Cao, X. (2020). Does any phenological event defined by remote sensing deserve particular attention? An examination of spring phenology of winter wheat in Northern China. Ecological Indicators116, 106456. https://doi.org/10.1016/j.ecolind.2020.106456
Han, H., Bai, J., Ma, G., & Yan, J. (2020). Vegetation phenological changes in multiple landforms and responses to climate change. ISPRS International Journal of Geo-Information9(2), 111. https://doi.org/10.3390/ijgi9020111
Huang, X., Liu, J., Zhu, W., Atzberger, C., & Liu, Q. (2019). The optimal threshold and vegetation index time series for retrieving crop phenology based on a modified dynamic threshold method. Remote Sensing11(23), 2725. https://doi.org/10.3390/rs11232725
Huete, A.R., Liu, H.Q., Batchily, K.V., & Van Leeuwen, W.J.D.A. (1997). A comparison of vegetation indices over a global set of TM images for EOS-MODIS. Remote sensing of environment59(3), 440-451. https://doi.org/10.1016/S0034-4257(96)00112-5
Izadi, H., Savari Mombeni, A., & Savari, M. (2022). Explaining the factors affecting the protection behavior of Zagros forests using the Norm Activation Model (NAM). Iranian Journal of Forest14(3), 307-327. https://doi.org/10.22034/ijf.2022.313453.1811 (In persian)
Kiapasha, K.H., Darvishsefat, A.A., Zargham, N., Julien, Y., Sobrino, J.A., & Nadi, M. (2017). Shifts of Start and End of Season in Response to Air Temperature Variation Based on Gimms Dataset in Hyrcanian Forests. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences42, 155-160. https://doi.org/10.5194/isprs-archives-XLII-4-W4-155-2017
Kowalski, K., Senf, C., Hostert, P., & Pflugmacher, D. (2020). Characterizing spring phenology of temperate broadleaf forests using Landsat and Sentinel-2 time series. International Journal of Applied Earth Observation and Geoinformation92, 102172. https://doi.org/10.1016/j.jag.2020.102172
Liu, J., Zhu, W., Atzberger, C., Zhao, A., Pan, Y., & Huang, X. (2018). A phenology-based method to map cropping patterns under a wheat-maize rotation using remotely sensed time-series data. Remote Sensing10(8), 1203. https://doi.org/10.3390/rs10081203
Masihpoor, M., Darvishsefat, A.A., Rahmani, R., & Fateh, P. (2021). Phenological parameters trend of the southern Zagros forests based on MODIS-NDVI time series during 2000-2017. Iranian Journal of Forest, 12(4), 577-590. https://doi.org/10.22034/ijf.2021.127807. (In persian)
Matsushita, B., Yang, W., Chen, J., Onda, Y., & Qiu, G. (2007). Sensitivity of the enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) to topographic effects: a case study in high-density cypress forest. Sensors7(11), 2636-2651. https://doi.org/10.3390/s7112636
McCloy, K.R. (2010). Development and evaluation of phenological change indices derived from time series of image data. Remote Sensing2(11), 2442-2473. https://doi.org/10.3390/rs2112442
Miri, N., Fatehi, P., Darvishsefat, A.A., Bavaghar, M.P., & Homolová, L. (2024). Leaf area index estimation in the Zagros forests of Iran using Sentinel-2 image and Gaussian Process Regression. Iranian Journal of Forest and Poplar Research31(4). https://doi.org/10.22092/ijfpr.2023.364041.2129 (In persian)
Salehi, A., & Eriksson, L.O. (2010). A Management Model for Persian Oak A Model for Management of Mixed Coppice Stands of Semiarid Forests of Persian Oak. Mathematical and Computational Forestry & Natural-Resource Sciences (MCFNS)2(1), 20-29.
Son, N.T., Chen, C.F., Chen, C.R., Minh, V.Q., & Trung, N.H. (2014). A comparative analysis of multitemporal MODIS EVI and NDVI data for large-scale rice yield estimation. Agricultural and forest meteorology197, 52-64. https://doi.org/10.1016/j.agrformet.2014.06.007
Stanimirova, R., Cai, Z., Melaas, E.K., Gray, J.M., Eklundh, L., Jönsson, P., & Friedl, M.A. (2019). An empirical assessment of the MODIS land cover dynamics and TIMESAT land surface phenology algorithms. Remote Sensing11(19), 2201. https://doi.org/10.3390/rs11192201
Sun, Q., Jiao, Q., Qian, X., Liu, L., Liu, X., & Dai, H. (2021). Improving the retrieval of crop canopy chlorophyll content using vegetation index combinations. Remote Sensing13(3), 470. https://doi.org/10.3390/rs13030470
Testa, S., Soudani, K., Boschetti, L., & Mondino, E.B. (2018). MODIS-derived EVI, NDVI and WDRVI time series to estimate phenological metrics in French deciduous forests. International journal of applied earth observation and geoinformation64, 132-144. https://doi.org/10.1016/j.jag.2017.08.006
Tian, J., Zhu, X., Chen, J., Wang, C., Shen, M., Yang, W., ... & Li, Z. (2021). Improving the accuracy of spring phenology detection by optimally smoothing satellite vegetation index time series based on local cloud frequency. ISPRS Journal of Photogrammetry and Remote Sensing180, 29-44. https://doi.org/10.1016/j.isprsjprs.2021.08.003
Tucker, C.J. (1979). Red and photographic infrared linear combinations for monitoring vegetation. Remote sensing of Environment8(2), 127-150. https://doi.org/10.1016/0034-4257(79)90013-0
Vaiphasa, C. (2006). Consideration of smoothing techniques for hyperspectral remote sensing. ISPRS journal of photogrammetry and remote sensing60(2), 91-99. https://doi.org/10.1016/j.isprsjprs.2005.11.002
Verrall, B., & Pickering, C.M. (2020). Alpine vegetation in the context of climate change: A global review of past research and future directions. Science of the Total Environment748, 141344. https://doi.org/10.1016/j.scitotenv.2020.141344
Vrieling, A., Meroni, M., Darvishzadeh, R., Skidmore, A.K., Wang, T., Zurita-Milla, R., ... & Paganini, M. (2018). Vegetation phenology from Sentinel-2 and field cameras for a Dutch barrier island. Remote sensing of environment215, 517-529. https://doi.org/10.1016/j.rse.2018.03.014
Xu, X., Conrad, C., & Doktor, D. (2017). Optimising phenological metrics extraction for different crop types in Germany using the moderate resolution imaging spectrometer (MODIS). Remote Sensing9(3), 254. https://doi.org/10.3390/rs9030254
Zarei, A.R., Shabani, A., & Mahmoudi, M.R. (2019). Comparison of the climate indices based on the relationship between yield loss of rain-fed winter wheat and changes of climate indices using GEE model. Science of the Total Environment661, 711-722. https://doi.org/10.1016/j.scitotenv.2019.01.204
Zhang, Q., Kong, D., Shi, P., Singh, V.P., & Sun, P. (2018). Vegetation phenology on the Qinghai-Tibetan Plateau and its response to climate change (1982–2013). Agricultural and forest meteorology248, 408-417. https://doi.org/10.1016/j.agrformet.2017.10.026
Zhang, J., Zhao, J., Wang, Y., Zhang, H., Zhang, Z., & Guo, X. (2020). Comparison of land surface phenology in the Northern Hemisphere based on AVHRR GIMMS3g and MODIS datasets. ISPRS Journal of Photogrammetry and Remote Sensing169, 1-16. https://doi.org/10.1016/j.isprsjprs.2020.08.020
Zhao, J., Zhang, H., Zhang, Z., Guo, X., Li, X., & Chen, C. (2015). Spatial and temporal changes in vegetation phenology at middle and high latitudes of the Northern Hemisphere over the past three decades. Remote Sensing7(8), 10973-10995. https://doi.org/10.3390/rs70810973
Zhou, X., Geng, X., Yin, G., Hänninen, H., Hao, F., Zhang, X., & Fu, Y.H. (2020). Legacy effect of spring phenology on vegetation growth in temperate China. Agricultural and Forest Meteorology281, 107845. https://doi.org/10.1016/j.agrformet.2019.107845

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