Clear Sky Calculator 2.0.5
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Free Version
Publisher Description
The Clear Sky Calculator is used to determine the need for recalibration of radiation sensors. It is most accurate when used near solar noon in the summer months. The calculator estimates the intensity of solar radiation (either total global shortwave radiation, measured by pyranometers, or global photosynthetic photon flux density, measured by quantum sensors) incident on a horizontal surface at any time of the day, at any location in the world. The equations used to estimate clear sky solar radiation with the Clear Sky Calculator come from the clear sky solar radiation model used to calculate net radiation in the ASCE Standardized Reference Evapotranspiration Equation (http://www.kimberly.uidaho.edu/water/asceewri/index.html). The only input requirements to the calculator are site elevation, latitude, longitude, reference longitude, air temperature and relative humidity measurements or estimates. These data are typically easy to obtain, making the Clear Sky Calculator a simple solar radiation reference that can be used to estimate pyranometer and quantum sensor accuracy and determine the need for recalibration.
When used near solar noon over multiple clear, unpolluted days during spring and summer months, accuracy of the Clear Sky Calculator is estimated to be ± 4 % in all climates and locations around the world. As an example, modeled incoming shortwave radiation (SWi) from the Clear Sky Calculator closely tracked measured SWi (data from a heated and ventilated Kipp & Zonen CM21 pyranometer) for a clear day (April 21, 2012) in Logan, Utah. The ratio of measured SWi to modeled SWi was between 1.00 and 1.05 (0 % and 5 %) from 9 AM to 6 PM (solar zenith angles less than 65∞). The average ratio from two hours before solar noon to two hours after solar noon was 1.02 ± 0.01 (2 ± 1 %). (see http://www.apogeeinstruments.com/using-the-clear-sky-calculator/ )
A more detailed discussion of Clear Sky Calculator accuracy is given on the webpage (http://clearskycalculator.com/model_accuracy.htm), where the necessary accuracy of the required inputs is discussed.
Apogee strongly encourages our customers to use the Clear Sky Calculator as an effective way to monitor pyranometer and quantum sensor performance and determine the need for sensor recalibration. If a sensor is consistently different from the Clear Sky Calculator by more than a few percent, please contact us about recalibration.
Sep 28, 2021
Version 2.0.5
Added ePAR option
About Clear Sky Calculator
Clear Sky Calculator is a free app for iOS published in the Office Suites & Tools list of apps, part of Business.
The company that develops Clear Sky Calculator is Apogee Instruments. The latest version released by its developer is 2.0.5.
To install Clear Sky Calculator on your iOS device, just click the green Continue To App button above to start the installation process. The app is listed on our website since 2021-09-28 and was downloaded 6 times. We have already checked if the download link is safe, however for your own protection we recommend that you scan the downloaded app with your antivirus. Your antivirus may detect the Clear Sky Calculator as malware if the download link is broken.
How to install Clear Sky Calculator on your iOS device:
- Click on the Continue To App button on our website. This will redirect you to the App Store.
- Once the Clear Sky Calculator is shown in the iTunes listing of your iOS device, you can start its download and installation. Tap on the GET button to the right of the app to start downloading it.
- If you are not logged-in the iOS appstore app, you'll be prompted for your your Apple ID and/or password.
- After Clear Sky Calculator is downloaded, you'll see an INSTALL button to the right. Tap on it to start the actual installation of the iOS app.
- Once installation is finished you can tap on the OPEN button to start it. Its icon will also be added to your device home screen.
