##IDL-Code from Papers at ETH Zurich: Hirschi M., B. Mueller, W. Dorigo and S. I. Seneviratne (2014): Using remotely sensed soil moisture for land-atmosphere coupling diagnostics: The role of surface vs. root-zone soil moisture variability. Remote Sensing of Environment, doi:10.1016/j.rse.2014.08.030.
Mueller, B. and S.I. Seneviratne (2012): Hot days induced by precipitation deficits at the global scale. Proceedings of the National Academy of Sciences of the United States of America, 109 (31), 12398-12403, doi: 10.1073/pnas.1204330109
##Main code calculating correlations:
corr_SPI_HD.pro
This function can read in any of the SPI-like and HotDay-like data used for both Hirschi et al. (2014) and Mueller and Seneviratne (2012). corr_SPI_HD.pro saves the correlations in NetCDF files for future reference and also creates the plots that appear in the Hirschi-paper. There is a description what the function does and how to properly call it in the header.
The figure that it produces is, for example the left hand side of:
showing the correlations between number of hot days and preceding drought index calculated from GLDAS NOAH in this case (select NOAH keyword). The hatching identifies areas with 90% significance level for correlations.
The code uses the sub-functions in this directory: read_GLDAS.pro, read_HD.pro and read_monthly_EI_Temp.pro to read in the data needed.
##Sub code calculating Hot Days:
heatw_temp_percentiles_5d.pro reads in the daily temperature data from different sources that you can choose with a keyword, and then calculates the number of days where the temperature is above the 90-th-percentile of the longterm 5 days-value around the date (not averaged, just the 5 values). If exceedance keyword is used, it will calculate the Temperature Exceedance in K - used in the Supplementary material of Mueller-paper - instead of the number of days.
To prepare the downloaded ERA-Interim or other sources temperature, the code prepare_daily_temp.pro extracts the maximum daily temperature from several (usually 4) values a day and saves them in NetCDF to be read in and used in heatw_temp_percentiles_5d.pro.