What is the term for lines on a map that join areas with equal sunshine?

The term for lines on a map that join areas with equal sunshine is "isohels." Isohels specifically represent the distribution of sunlight across different regions, indicating areas that receive the same amount of solar radiation over a given period. This is particularly useful in studies related to climatology, agriculture, and energy generation, as it helps to illustrate variations in sunlight exposure due to geographical features, seasonality, and weather patterns.

Understanding the distinction between isohels and similar terms can clarify their specific applications. Isohyets, for example, refer to lines that connect points of equal precipitation, while isotherms connect areas of equal temperature, and isobars connect points of equal atmospheric pressure. Each of these terms provides valuable information in their respective fields, but isohels is the precise term for mapping sunshine.