---
title: "Solar Radiation Data Fields | Definitions"
slug: "solar-radiation-data-fields"
description: "Learn the data inputs and appropriate datafile format for solar radiation data fields when using the water quality solver. "
tags: ["1D river modelling"]
updated: 2022-08-05T06:48:04Z
published: 2022-08-05T06:48:04Z
canonical: "help.floodmodeller.com/solar-radiation-data-fields"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.floodmodeller.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Solar Radiation Data Fields

## Data Input

In order to input the required information for this pollutant into the Water Quality model, the user needs to make sure that the Tab Solar Radiation appears in the WQ General Tab (please follow the description on the page [Preparing a Water Quality Datafile](/v1/docs/preparing-a-water-quality-datafile) for this). Then the user needs to select the Tab Solar Radiation (as shown on the Figure below) and type in the necessary information for this pollutant in the format documented in the section Datafile Format below. Alternatively the necessary information for this pollutant can be typed in the .con file opened in a Textpad editor in the datafile format mentioned below. ![WaterQualityimagesimage18.jpg](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/WaterQualityimagesimage18.jpg)

## Datafile Format

*(1)* *If the user wishes to specify* *hourly* *values of solar radiation between 5:00 and 20:00 hours of each day use:*

Line 1 SOLAR RADIATION

Line 2 HOURLY

Line 3 mday, mmonth, myear

Lines 4 & 5 solcon(lday) lday = 5,20 (2 lines)

*Lines 3 to 5 are repeated for each day of the simulation.*

Last line SOLAREND

Where:

SOLAR RADIATION = keyword

HOURLY = keyword

mday, mmonth, myear = Date of subsequent solar radiation data.

solcon(lday) lday = Amount of solar radiation (J/cm2) over each hour from 5am to 8pm

SOLAREND = keyword

*(2)* *If the user wishes to specify daily values of solar radiation then use:*

Line 1 SOLAR RADIATION

Line 2 DAILY

Line 3 mday, mmonth, myear

Lines 4 lenday, solcon

*Lines 3 and 4 are repeated for each day of the simulation.*

Last line SOLAREND

Where:

DAILY = keyword

lenday = Length of day (hours),

solcon = amount of solar radiation over a typical hour during the day (J/cm2).

*(3)* *If the user wishes to set a constant solar radiation for the whole of the simulation use:*

Line 1 SOLAR RADIATION

Line 2 CONSTANT

Lines 4 lenday, solcon

Last line SOLAREND

Where:

CONSTANT = keyword

lenday, solcon = Length of day (hours) used throughout the whole simulation, amount of solar radiation over a typical hour for use throughout out the whole simulation (J/cm2).

Note: The equations used to determine light limitation include light only as the ratio I/Imax. The actual units used for light are therefore irrelevant provided that the same units are used for I and Imax. Normally the 1D Water Quality Solver assumes units of J/cm2.

---

Overview

[Solar Radiation](/v1/docs/solar-radiation)