HadCRUH is a 5 by 5 degree monthly mean anomaly near-global (land and marine) surface humidity dataset. It currently begins in 1973 and ends in 2003. It is available in specific and relative humidity. It will shortly be available for free online from the Hadley Centre.
The creation of this dataset is the basis of my thesis. Great efforts are taken to quality control and homogenise the data. This is a first version dataset with much scope for improvement in quality, resolution and spatial coverage. At present no uncertainty estimates are available.
Please see my thesis for a full description of building HadCRUH.
The surface humidity data are analysed alongside global temperature trends from the Hadley Centre and Climatic Research Unit dataset HadCRUT3 and specific humidity output from the global circulation model HadCM3. This analysis focuses on global scale trends and timeseries. A very basic model validation and attribution analysis is made.
Please see my thesis for the results of these anyaleses. Published papers to follow in the not too distant future...hopefully!