AFT HMI Baseline

This version of the AFT HMI Baseline was created by assimilating hourly HMI.M_720s magnetograms (http://jsoc.stanford.edu/HMI/Magnetograms.html) beginning May 1rst 2010 through May 1rst 2021. AFT maps for this series are output at a cadence of 8 hours per day (at 0,8, and 16 hours). The data for each year are saved into a separate directory. The output data are provided as both as data file (.dat) and the accompaning image file (.gif). IDL code to read in the AFT maps in the .dat file format: a1=assoc(1,fltarr(1024,512)) dateString=Year + Month + Day mapString=dateString + '.00' mapFile=Path + Year + '\' + mapString + '.dat' openr,1,mapFile bmap=a1(0) close,1 Each file is a 1024x512 array in longitude and latitude. The longitude of each pixel is given by longitude=fltarr(1024) for i = 0, 1023 do longitude(i)=(i+0.5)*360./1024. The latitude values of each pixel is given by latitude=fltarr(512) for j=0,511 do latitude(j)=-90. + (j+0.5)*180./512. I will be updating the file format to the .fits files, including relevant keywords. In the meantime, if you have any questions or if you need a specialized AFT series (e.g., different cadence) please feel free to reach out to me.

本版AFT HMI基线数据集（AFT HMI Baseline）通过同化2010年5月1日至2021年5月1日期间的每小时HMI.M_720s磁图（http://jsoc.stanford.edu/HMI/Magnetograms.html）构建而成。该序列的AFT图每日以8小时间隔输出（分别在0时、8时和16时）。每年的数据均存储于独立目录中。输出数据同时提供.dat格式数据文件与.gif格式配套图像文件。以下为读取.dat格式AFT图的IDL代码：
a1=assoc(1,fltarr(1024,512))
dateString=Year + Month + Day
mapString=dateString + '.00'
mapFile=Path + Year + '\' + mapString + '.dat'
openr,1,mapFile
bmap=a1(0)
close,1
每个文件为1024×512的经纬度阵列。各像素的经度计算方式为：令longitude为长度1024的浮点数组，对于i从0至1023，有longitude(i)=(i+0.5)*360./1024。各像素的纬度计算方式为：令latitude为长度512的浮点数组，对于j从0至511，有latitude(j)=-90. + (j+0.5)*180./512。我方将把文件格式更新为.fits格式，并添加相关关键字。在此期间，若您有任何疑问或需要定制化AFT序列（例如不同的采样间隔），欢迎随时联系我方。