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A Deeper Look: Land Surface Temperatures in Ghana, by Month


This post explores the dynamics of Land Surface Temperature (LST) across Ghana, based on an analysis of Google Earth Engine data. This investigation is part of a broader project examining economic and environmental shocks and their impact on social protection beneficiaries in Ghana.

What is Land Surface Temperature and Why Does it Matter?

Often confused with air temperature, Land Surface Temperature (LST) is the "skin temperature" of the earth's surface—a measure of how hot or cool the ground is to the touch. This metric is vital for understanding our environment for several key reasons:

  • Climate and Weather: LST influences local and regional weather patterns, including the formation of clouds and rainfall.

  • Agriculture: Crop health, growth, and water needs are directly tied to the temperature of the soil. High LST can lead to rapid moisture evaporation and severe agricultural stress.

  • Human Health: In populated areas, high LST contributes to the "Urban Heat Island" effect, exacerbating heat waves and increasing the risk of heat-related illness for vulnerable populations.

  • Ecology: It affects the habitats of plants and animals and the rate of vegetation growth.

The Geographic Context of Ghana's Climate

Ghana's climate is quintessentially tropical, driven by its position on the Gulf of Guinea, just a few degrees north of the Equator. This location creates a distinct climatic split:

  • The South-West: This region is characterized by a hot and humid equatorial climate. The proximity to the ocean and the presence of rainforests help to moderate temperature extremes.

  • The North: This region features a hot and dry tropical savanna climate. It is significantly influenced by the Harmattan, a dry, dusty wind from the Sahara that blows from approximately December to March, leading to higher daytime temperatures and cooler nights.

Visualizing the Data: Monthly LST Variations

The animated maps below, created using Google Earth Engine, visualize these climatic patterns by showing how LST changes across Ghana's districts throughout the year.

1. The Annual LST Cycle

This first animation provides a comprehensive overview of the LST cycle across Ghana. You can clearly observe the distinct seasonal pulse: temperatures climb across the entire nation, peaking around March and April, just before the onset of the main rainy season, which brings cloud cover and cooling. The northern regions consistently demonstrate higher peak temperatures, reflecting their arid climate.

2. Day vs. Night: A Tale of Two TemperaturesTo fully understand the thermal environment, it's crucial to differentiate between daytime and nighttime temperatures. The following two animations split the data to show these distinct periods.

The Daytime LST map (above) highlights the impact of direct solar radiation. It vividly illustrates how the northern savanna regions, which have less dense vegetation and cloud cover, absorb intense heat. You can also infer how different land covers react; urban areas and bare soil will heat up significantly more during the day than forested or water-covered areas.


Conversely, the Nighttime LST map (above) shows how different surfaces retain or radiate heat after sunset. The south-west, with its high humidity and forest cover, tends to stay warm and humid at night. In contrast, the arid northern regions, while intensely hot by day, often cool down more significantly at night. This day-night difference, known as the diurnal temperature range, is a critical factor for both agriculture and human well-being.

Implications for Vulnerable Populations

These LST variations are not just a climate curiosity; they represent a direct potential shock to households, particularly those reliant on agriculture.

  • Agricultural Shocks: High land surface temperatures, especially during the crucial pre-rainy season, can lead to rapid soil moisture evaporation. This can stress staple crops like maize and yams, or cash crops like cocoa, which are vital to the livelihoods of many social protection beneficiaries.

  • Health Shocks: Extreme daytime heat, particularly in the northern regions, increases the risk of heatstroke, dehydration, and other heat-related illnesses. This disproportionately affects the elderly, children, and outdoor laborers, who are often among the most vulnerable.

By mapping these temperature dynamics, this project aims to build a more granular understanding of environmental risks. The next step is to correlate this LST data with data on agricultural and health shocks to better identify, predict, and support the communities most at risk.


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