Although the perspective is conceptually useful, it provides an incomplete understanding of the physics driving the warming contrast. Rather than surface energy balance, atmospheric dynamics — the motion of the atmosphere and its thermodynamic state — underpin a new understanding of the land-ocean warming contrast that has developed over the last decade. In a paper , Prof Manoj Joshi — then at the Met Office Hadley Centre and the University of Reading and now at the University of East Anglia — was the first to point out that dynamical processes in the atmosphere connect temperature and humidity over land and ocean regions.
Specifically, he showed that the lapse rate — the rate of decrease of temperature with height — decreases more strongly over ocean than over land as climate warms. This is because the air above the ocean is, at any moment in time, typically holding more water vapour than the air over land. These contrasting lapse rate changes explain the warming contrast: a weaker decrease in land lapse rate implies a larger increase in land surface temperature relative to the ocean.
This mechanism is not necessarily intuitive, but relies on well-established processes in atmospheric dynamics. Differing lapse rate changes are now accepted as the fundamental driver of the land-ocean warming contrast, particularly at low latitudes up to approximately 40N and 40S.
Amplified warming in regions including the Mediterranean are also explained by the same lapse-rate mechanism. With his paper, Joshi introduced a new conceptual understanding for the land-ocean warming contrast.
But, again, the explanation was qualitative. The key insight was that although changes in temperature and humidity over land and ocean are very different, the atmospheric dynamics constraints identified by Joshi imply that changes in a particular combination of temperature and humidity — specifically, the energy contained in a parcel of air at rest, a quantity known as moist static energy — are approximately equal.
This insight allowed us to derive an equation for the land temperature change, which we published in The drier the land is, the more it warms. The theory has been verified in climate models and using observational data over the past 40 years.
The theory explains why land warming is expected to be particularly severe in dry, arid subtropical regions and also explains why relative humidity over land has been decreasing over recent decades.
Receive our free Daily Briefing for a digest of the past 24 hours of climate and energy media coverage, or our Weekly Briefing for a round-up of our content from the past seven days. Just enter your email below:. An important implication of the theory for projections of future land temperatures which vary considerably across models is that it is crucial to accurately model how dry land is in the current climate , but this is technically tricky due to the complexities of land surfaces.
This new understanding of the land-ocean warming contrast has been well received by the atmospheric dynamics and climate dynamics research communities. But it would be fair to say that it is still not well known in the broader climate science and climate impacts communities that the land-ocean warming contrast is driven by dryness rather than differences in heat capacity.
And it is certainly not well known in the public sphere. These air temperatures are not dissimilar from heating and cooling of land. However, during the day, water forms may only change in degree by a half degree, except for perhaps during the dog days of summer.
W hy Are Coastal Areas Cooler? Y ou may notice that in the summer, inland temperatures may be scorching hot, while coastal areas remain cooler.
This is directly caused by the ocean. Because water heats and cools more slowly and oceans only change by small amounts throughout the day or season, coastal areas remain cooler. In fact, heating and cooling differences between land and water affect the climate everywhere on earth. Land and Water Are Affected by Color. T he heating differences between land and water are affected by. Color also matters. Darker materials have a tendency to absorb more radiation sun energy , and this, in turn, can make land masses hotter.
T exture also has a lot to do with the differences in heating and cooling of land and water. Rough, dry materials absorb more heat. Cities make up quite a big part of the earth, and they are often mainly composed of asphalt and concrete, which both absorb more radiation. Provide temperature maps to each group of students see p. Allow time for them to study there maps and share observations with each other. Then ask each team to prepare generalizations they have gathered from the maps.
Prompt them to "Discuss the different temperature patterns you observe. Where are the highest temperature located?
Where are the lowest temperatures located? Compare coastal temperatures with temperatures further inland. Compare temperatures at different latitudes and elevations. Record these observations on an overhead transparency, chalkboard or large chart to facilitate whole class discussion. Based on what they have observed on the temperature maps and from their existing knowledge, challenge students to form a hypothesis about whether soil or water will heat faster, and which will cool faster.
Distribute Student Worksheet 1. Ensure each group has all the materials required and understands safety guidelines for the use of glassware and thermometers. Have students place ml of soil in one beaker and ml of water in the other beaker. They will then place a thermometer in each beaker and record the starting temperature.
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