We're a small engineering company and family business based in Colorado. We started collecting US solar radiation data because we needed it for a modeling project. You can read more about us at JHtech.com or SolarDataWarehouse.com. Our solar technology was acquired by an agricultural company and we continue improving our solar data for them.
Why do we have solar data?
We started collecting our solar radiation data as a part of a large-scale corn growth modeling project. The solar radiation is a key factor in modeling growth accurately, however, there isn't a good national dataset. We read several university papers mentioning that modeling the solar radiation was the best they could do, simply because the data wasn't available. We also spoke to a professional climatologist, who believed there were only a couple hundred US stations with solar radiation. He was very surprised to learn that we had found several thousand. The problem with these stations is that the units and data formats are not consistent, so we have spent a lot of time writing software that will collect the data each week and rationalize them all into a single database with the same units. The data collection itself has proven somewhat tempermental as well (stations appear and disappear, websites change, general internet issues), so the data collection requires some weekly maintenance.
We have also collected soil and yield data, and we offer the yield data as a product for farmers at CropFax.com. Soon we will be completing our new site that generates real-time yield forecasts on a field level. While it's hard to compete with the USDA's accuracy, we hope to be able to produce reliable yield forecasts several weeks before they can. We're also working to complete a real-time solar radiation system. Check out our paper in the 2012 ASES Conference!