The solar resource tool from landsat vs ground data project
We have different types of models to calculate the direct radiation of solar from ground data and the other one is the data of satellite that we can use for solar radiation measurement. In this report we have compared the different tools from ground data and LandSat.
One of the ways of getting accurate and reliable global radiation data for alternative energy system design is by ground measurements at the location of interest. Ground measurements are typically pinpoint measurements which are temporally integrated. This involves installation of solar sensor like pyranometer for continuous, long-term measurements of solar data. Compared to the measurements of other meteorological parameters, the equipment for radiation measurements is extremely expensive and requires experts for operation and maintenance. Although ground measure data are said to be accurate and reliable, the price implication and technicality involved have made such data unavailable in many locations. This has led to the rummage around for alternative means of getting solar data for research and development of alternative energy systems.
Global Horizontal Irradiance (GHI) is usually measured by (i) thermocouple based pyranometers or (ii) silicon photodiode cells. For development and monitoring of solar power plants, it’s advised to use high-standard meteorological pyranometers to attain the very best possible accuracy and stability of measurements. Direct Normal Irradiance (DNI) is measured by pyrheliometers, where the instrument always aims directly at the sun by continuously sun tracking mechanism. Optionally DNI are often measured by Rotating Shadow band Radiometer (RSR) or by integrated pyranometer such Sunshine Pyranometer (e.g. SPN1). Diffuse Horizontal Irradiance (DIF) is measured by (i) pyranometers, which obscure the direct radiation with a sun tracking disk or an adjustable fixed shadow ring, or (ii) by RSR equipped with rotating shadow band. Diffuse radiation can be also calculated as a difference between global and direct components. However, this method isn’t ideal because it increases uncertainty compared to a zealous measurement and doesn’t allow full quality testing of measurements should be considered, appropriate correction techniques must be applied to obtain accurate results.
Reliable solar models supported the employment of satellite and atmospheric data exist today. an honest description of the current approaches may be consulted in. In brief, the
state-of-the-art high-accuracy modelling approaches have the following features:
- Use of recent models supported sound theoretical grounds, which are regionally and temporally consistent and computationally stable.
- Use of the state-of-the-art input data: satellite, aerosols, water vapor, etc. These computer files are systematically quality controlled and validated.
- Models and computer file are integrated and regionally adapted to perform reliably at a large range of geographical conditions.