Vaisala Energy Support
What is the “TMY” Data Type in the Solar Time Series Download tool?
The “TMY” data type will create a data file that covers a single year at hourly resolution, sometimes called an 8760 for the number of data rows in the file. TMY stands for Typical Meteorological Year and this file is meant to represent “typical” conditions at a site. The TMY files from the Solar Time Series Tools are both "GHI-" and “DNI-conserving," meaning that the means of these variables are targeted to tightly match the long-term means.
Vaisala uses a proprietary method for TMY creation. Starting from the long-term time series, we determine the long-term annual and monthly means as well as monthly diurnal patterns. We then choose 4-day periods from across the dataset to create a month, for example Jan 1-4 may be from 1998, Jan 5-8 from 2005, and so on. Once we have a complete month, we verify that it matches the long-term monthly mean to within in 0.5% for GHI and 1% for DNI. Once we have 12 months created, we check to make sure GHI and DNI match their long-term annual means to within 0.3% and 0.5%, respectively.
More Solar Online Tools Questions
- How accurate is the data in the Solar Time Series Tools?
- The datasets give different answers. Which one is right?
- Why are there so many (5) different versions of solar data?
- Which weather data source should I pick?
- Why do the values in my TMY file change?
- What updates were applied to the datasets in November 2019?
- What's the latest month available in the solar time series tool?
- What solar values are shown on the map in solar prospecting and solar time series tool?
- 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 1.2 dataset?
- What is the Vaisala 2.0 dataset?
- What is the Vaisala 2.1 dataset?
- What are the units of irradiance?
- 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.