Vaisala Energy Support
What is the Vaisala 1.2 dataset?
The Vaisala 1.2 dataset is the third dataset created by Vaisala, then 3TIER. The main change from the V1.1 dataset was increasing the temporal resolution of the MODIS aerosol and water vapor inputs from monthly to daily. Four MODIS data streams are still used to derive the satellite aerosol values.
The clear sky model used is based on the Perez SUNY v1.0 methodology, as described in R. Perez et al., “A new operational model for satellite-derived irradiances: Description and validation," Solar Energy, Vol. 73, Iss. 5, November 2002, pages 307-317.
The primary difference between the Vaisala 1.2 and Perez v1.0 clear sky algorithms is that the Linke coefficient used here is derived using a Vaisala proprietary method incorporating the MODIS aerosol optical depth and water vapor dataset mentioned above, using Ineichen's “Conversion function between the Linke turbidity and the atmospheric water vapor and aerosol content,” Solar Energy, 82, 1095-1097.
Vaisala uses a proprietary cloud index calculation methodology to compute cloudy sky irradiance. To derive the cloud index, the satellite radiance measurements are first processed to account for instrument degradation over time. The Vaisala cloud algorithm then divides the satellite measurements into bins by solar azimuth and zenith angle, and treats each bin independently for the calculation of a cloud index. The fit between cloud index, clear-sky GHI, and observations is done on a per satellite basis.
More Solar Online Tools Questions
- Which weather data source should I pick?
- What's the latest month available in the solar time series tool?
- What updates were applied to the datasets in November 2019?
- What solar values are shown on the map?
- How do I enter a location?
- Why does the map disappear?
- How do I interpret the graphs provided by the Monthly Mean Irradiance Tools in the Prospecting Tools?
- What do the Annual Mean Irradiance Tools in the Prospecting Tools provide?
- How can I compare sites side-by-side in the Prospecting Tools?
- How much area is covered by the Solar Prospecting Tools?
- How accurate are the Solar Prospecting Tools?
- What data is shown in the Solar Time Series Viewer?
- What data can I get from the Solar Time Series Download tool?
- What is the Vaisala 1.0 dataset?
- What is the Vaisala 1.1 dataset?
- What is the Vaisala 2.0 dataset?
- What is the Vaisala 2.1 dataset?
- The datasets give different answers. Which one is right?
- How accurate is the data in the Solar Time Series Tools?
- What are the units of irradiance?
- What is the “TMY” Data Type in the Solar Time Series Download tool?
- What is the “Long-Term” Data Type in the Solar Time Series Download tool?
- Why does the data not match my observations?
- How do I input CSV files into PVSyst?
- How can I input time series data into PVSyst?
- What is Global Horizontal Irradiance?
- What is Direct Normal Irradiance?
- What is Diffuse Horizontal Irradiance?
- What affects solar radiation at a given site?
If you didn't find what you were looking for, please contact 3TIER Support for additional assistance.