MEGANv2.1 1km2 global monthly LAIv for 2003

These files contain global monthly estimates of the Leaf Area Index of vegetation covered surfaces (LAIv) at a spatial resolution of 30 sec longitude x 30 sec latitude (about 1 km2). The values are representative of the m2 of one sided leaf area per m2 of vegetation covered area. For example, if the LAI for a specific location is 2 m2/m2 and the vegetation cover fraction is 0.4 (i.e., 40% of the surface is covered by vegetation) then the LAIv = LAI/VCF = 2/0.4 = 5. There are 12 netcdf format files (one for each month of 2003). The file naming convention is laiv2003MM where MM is month of the year. The units are m2 leaf area per 10 m2 surface area (which is the unit expected for the MEGANv2.1 preprocessor) These files were created in 2005 for use in MEGANv2 as described by Guenther et al. 2006 (doi.org/10.5194/acp-6-3181-2006). They are based on MODIS (MOderate Resolution Imaging Spectroradiometer) satellite LAI estimates described by Zhang et al JGR (2004) doi:10.1029/2004JD004720 and the vegetation cover fraction of Hansen et al. Earth Interactions 7: 1-15 (2003). Urban and wetland areas and other regions with missing LAI data in this MODIS database were assigned an LAIv based on the average for the surrounding region.

本数据集包含植被覆盖地表叶面积指数（Leaf Area Index of Vegetation Covered Surfaces，LAIv）的全球月度估算结果，空间分辨率为30角秒经度×30角秒纬度（约1平方千米）。该数值代表每平方米植被覆盖区域内的单侧叶面积平方米数。例如，若某一特定位置的叶面积指数（Leaf Area Index，LAI）为2 m²/m²，且植被覆盖分数（Vegetation Cover Fraction，VCF）为0.4（即地表40%被植被覆盖），则LAIv = LAI/VCF = 2/0.4 = 5。本数据集包含12个netCDF格式文件，分别对应2003年的每个自然月。文件命名规则为laiv2003MM，其中MM代表年度中的月份序号。数据单位为每10平方米地表面积对应的叶面积平方米数，该单位符合MEGANv2.1预处理程序的要求。本数据集文件于2005年生成，用于MEGANv2模型，相关说明详见Guenther等人2006年发表的研究（doi.org/10.5194/acp-6-3181-2006）。本数据集基于MODIS（Moderate Resolution Imaging Spectroradiometer，中分辨率成像光谱仪）卫星的叶面积指数估算结果（详见Zhang等人2004年发表于《Journal of Geophysical Research》的研究，doi:10.1029/2004JD004720），以及Hansen等人2003年发表于《Earth Interactions》第7卷第1-15页的植被覆盖分数数据。对于该MODIS数据库中缺失叶面积指数数据的城市、湿地及其他区域，我们基于周边区域的平均值为其赋予LAIv数值。