植被叶面积指数（leaf area index,LAI）也称叶面积系数，可表征植被对光线的吸收和拦截以及植被生长状况，通常被定义为单位面积内所含的植被叶片表面积之和。因该指数可反映研究区内植被叶片的疏密程度及植被的生长状况，所以精确获取LAI显得极为重要。\n
在LAI的获取过程中，遥感信息技术因其可实时动态有效监测植被特征且作业周期短等显著优势而被广泛应用，该技术为植被生化参数的有效研究奠定了基础。", "ds_source": "
数据来源于NASA官网(https://ladsweb.modaps.eosdis.nasa.gov)。\n
涉及MCD15A2H数据包括：h26v05、h27v05，数据分辩率为500m，8天合成；渭河流域边界。", "ds_process_way": "
（1）试运行MRT工具，生成MCD15A2 LAI数据拼接和投影转换的prm文件,空间分辨率为500m。
\n
（2）利用MATLAB 语言程序生成调用MRT工具的批处理文件，并运行。
\n
（3）利用渭河流域矢量边界，采用Python批量裁剪等步骤，以tif格式存储。", "ds_quality": "
本数据集与源数据集MODIS MCD15A2.006质量一致。数据有效范围0-100，放缩因子为0.1，填充值范围249-255，其中：249表示 “未分类”或无法确定的土地覆盖类型；250表示城镇/建成区的土地覆盖类型；251表示“永久”湿地/泛滥沼泽的土地类型；252表示常年积雪或冰覆盖的土地；253表示贫瘠、稀疏的植被(如岩石、苔原、沙漠等)；254表示永久性盐碱地或内陆水体覆盖区；255表示用于计算MCD15A2数据的源数据MOD09等地表反射红外近红外波段数据出现填充值时，对应MCD15A2像元填充为255，有的填充为254。", "ds_acq_start_time": "2002-07-04 00:00:00", "ds_acq_end_time": "2020-12-31 00:00:00", "ds_acq_place": "渭河流域,甘肃省,陕西省,宁夏回族自治区", "ds_acq_lon_east": 110.27444444444444, "ds_acq_lat_south": 33.69611111111111, "ds_acq_lon_west": 103.9713888888889, "ds_acq_lat_north": 37.40833333333333, "ds_acq_alt_low": null, "ds_acq_alt_high": null, "ds_share_type": "login-access", "ds_total_size": 1000485430, "ds_files_count": 30637, "ds_format": "tif", "ds_space_res": "500", "ds_time_res": "8天", "ds_coordinate": "WGS84", "ds_projection": "", "ds_thumbnail": "baa34def-568e-474d-985f-a4923fd87295.jpg", "ds_thumb_from": 2, "ds_ref_way": "", "paper_ref_way": "", "ds_ref_instruction": "", "ds_from_station": null, "organization_id": "0d5fea4e-6fd7-4c70-b28b-3f91204c579a", "ds_serv_man": "敏玉芳", "ds_serv_phone": "0931-4967596", "ds_serv_mail": "ncdc@lzb.ac.cn", "doi_value": "", "subject_codes": [ "170.4510" ], "quality_level": 3, "publish_time": "2021-11-05 10:52:05", "last_updated": "2025-05-29 11:35:52", "protected": false, "protected_to": null, "lang": "zh", "cstr": "11738.11.ncdc.WRiver.2021.34", "i18n": { "en": { "title": "Leaf area index LAI for the Weihe River Basin MCD15A2 (2002-2020)", "ds_format": "tif", "ds_source": "
Data from NASA's official website (https://ladsweb.modaps.eosdis.nasa.gov).\n
Data involving MCD15A2H include: h26v05, h27v05, data resolution 500m, 8 days of synthesis; Weihe River Basin boundary.", "ds_quality": "
This dataset is consistent in quality with the source dataset MODIS MCD15A2.006. The data has a valid range of 0-100, a deflation factor of 0.1, and a range of fill values of 249-255, where: 249 indicates “unclassified” or undeterminable land cover type; 250 indicates land cover type of towns/built-up areas; 251 indicates “permanent “ wetland/floodplain swamp land cover type; 252 denotes land covered by perennial snow or ice; 253 denotes barren, sparse vegetation (e.g., rocky, tundra, desert, etc.); 254 denotes permanent saline or inland water cover area; and 255 denotes surface reflectance infrared near-infrared (IRNIR) bands such as MOD09, which is the source data used to compute MCD15A2 data When a fill value appears, the corresponding MCD15A2 image element is filled with 255, and some are filled with 254.", "ds_ref_way": "", "ds_abstract": "
The leaf area index (LAI), also known as the leaf area coefficient, characterizes the absorption and interception of light and the growth of vegetation, and is usually defined as the sum of the surface area of vegetation leaves per unit area. Because this index can reflect the sparseness of vegetation leaves and the growth of vegetation in the study area, it is extremely important to accurately obtain LAI.\n
In the acquisition process of LAI, remote sensing information technology is widely used because of its significant advantages such as real-time dynamic and effective monitoring of vegetation characteristics and short operation cycle, which lays the foundation for the effective research of vegetation biochemical parameters.
", "ds_time_res": "8天", "ds_acq_place": "Weihe River Basin, Gansu Province, Shaanxi Province, Ningxia Hui Autonomous Region", "ds_space_res": "500", "ds_projection": "", "ds_process_way": "(1) Trial run of the MRT tool to generate prm files for MCD15A2 LAI data splicing and projection conversion, with a spatial resolution of 500m.\n
(2) Generate a batch file to call the MRT tool using the MATLAB language program and run it.\n
(3) Utilizing the vector boundaries of the Weihe River Basin, using steps such as Python batch cropping, and storing in tif format.", "ds_ref_instruction": "" } }, "submit_center_id": "ncdc", "data_level": 0, "license_type": "CC BY 4.0", "doi_reg_from": "reg_local", "cstr_reg_from": "reg_local", "doi_not_reg_reason": null, "cstr_not_reg_reason": null, "is_paper_in_submitting": false, "ds_topic_tags": [ "MCD15A2", "叶面积指数", "LAI" ], "ds_subject_tags": [ "自然地理学" ], "ds_class_tags": [], "ds_locus_tags": [ "渭河流域", "甘肃省", "宁夏回族自治区", "陕西省" ], "ds_time_tags": [ 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 ], "ds_contributors": [ { "true_name": "张耀南", "email": "yaonan@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "ds_meta_authors": [ { "true_name": "李红星", "email": "lihongxing@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "ds_managers": [ { "true_name": "敏玉芳", "email": "myf@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "category": "生态" }