Calculate the rate of water evaporation from a surface using various environmental factors.
Understanding Evaporation Rate
Evaporation is the process by which water changes from a liquid to a gas or vapor. It's a crucial part of the water cycle, influencing weather patterns, agriculture, and water resource management. The rate at which evaporation occurs is not constant; it depends on several environmental factors.
Factors Affecting Evaporation Rate:
Surface Area: A larger surface area exposes more water molecules to the atmosphere, increasing the potential for evaporation.
Wind Speed: Wind removes saturated air from above the water surface, allowing drier air to come into contact with it. This difference in moisture content drives further evaporation. Higher wind speeds generally lead to higher evaporation rates.
Temperature: Higher air and water temperatures provide more kinetic energy to water molecules, making it easier for them to break free from the liquid surface and become vapor.
Humidity: Relative humidity is the amount of water vapor in the air compared to the maximum amount it can hold at a given temperature. High humidity means the air is already saturated with water vapor, reducing the potential for more water to evaporate. Low humidity promotes faster evaporation.
Solar Radiation: Sunlight provides the energy needed for water to transition from liquid to gas. Surfaces exposed to direct sunlight will experience higher evaporation rates.
How the Calculator Works:
This calculator uses a simplified model to estimate the evaporation rate. While complex physical formulas like the Penman-Monteith equation are used in scientific contexts for high accuracy, this tool provides a general estimate based on the interplay of key factors. The calculation broadly considers how increased temperature and solar radiation enhance evaporation, while higher humidity and denser air (lower temperature) can reduce it. Wind speed plays a direct role in removing vapor from the surface.
The result is typically expressed in units like millimeters (mm) or inches (in) of water depth evaporated per unit of time (e.g., per day or per hour), depending on the specific formula used and the units of the input parameters. For this calculator, we will aim for a result in mm per day, assuming typical conditions.
Note: This calculator provides an approximation. Actual evaporation rates can be influenced by other factors such as water quality, surface roughness, and atmospheric pressure.
function calculateEvaporationRate() {
var surfaceArea = parseFloat(document.getElementById("surfaceArea").value);
var windSpeed = parseFloat(document.getElementById("windSpeed").value);
var temperature = parseFloat(document.getElementById("temperature").value);
var humidity = parseFloat(document.getElementById("humidity").value);
var solarRadiation = parseFloat(document.getElementById("solarRadiation").value);
var resultElement = document.getElementById("result");
resultElement.innerHTML = ""; // Clear previous results
if (isNaN(surfaceArea) || isNaN(windSpeed) || isNaN(temperature) || isNaN(humidity) || isNaN(solarRadiation)) {
resultElement.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (surfaceArea <= 0 || windSpeed < 0 || temperature 50 || humidity 100 || solarRadiation < 0) {
resultElement.innerHTML = "Please enter reasonable values for the inputs.";
return;
}
// Simplified evaporation model (conceptual – real models are more complex)
// This formula is a conceptual representation and not a scientifically validated formula like Penman-Monteith.
// It aims to show the general impact of variables.
// Formula idea: Evaporation increases with temperature, solar radiation, wind speed, and surface area.
// Evaporation decreases with humidity.
// Base evaporation rate, influenced by temperature and humidity.
// A higher temperature increases potential evaporation.
// A higher humidity decreases the actual evaporation.
var tempFactor = temperature * 0.5; // Arbitrary scaling for temperature impact
var humidityFactor = (100 – humidity) / 100; // Lower humidity means higher factor
// Wind speed contributes to removing saturated air.
var windFactor = windSpeed * 0.8; // Arbitrary scaling for wind impact
// Solar radiation provides energy.
var radiationFactor = solarRadiation / 100; // Arbitrary scaling for solar radiation impact
// Combine factors. Surface area is applied at the end.
// The overall rate is a product of these factors, with some adjustments.
// This is a highly simplified representation.
var estimatedRatePerArea = (tempFactor + windFactor + radiationFactor) * humidityFactor * 0.2; // Base rate scaling
// Ensure a minimum evaporation even in seemingly unfavorable conditions if inputs are valid
if (estimatedRatePerArea < 0.1) {
estimatedRatePerArea = 0.1;
}
var totalEvaporationRate = estimatedRatePerArea * surfaceArea;
// Scale the result to be roughly in mm per day for a reasonable example.
// This scaling is empirical and illustrative.
var finalRateMmPerDay = totalEvaporationRate * 0.5; // Further empirical scaling
// Ensure the final rate is not excessively high or low due to arbitrary scaling
if (finalRateMmPerDay 50) finalRateMmPerDay = 50; // Cap for reasonableness
resultElement.innerHTML = "Estimated Evaporation Rate: " + finalRateMmPerDay.toFixed(2) + " mm per day";
}