Climate Change and Photography
By Andy May
We’ve seen a lot of news stories about an upcoming El Niño, that may turn into a so-called “super” El Niño over the next year. This will affect our weather for a year or two, but what is the climatic effect of this weather feature, if any? Here we examine the history of warm ENSO events.
Continue reading “Do Los Niños cause climatic cooling?” By Andy May
The moist‑adiabatic theory (Durran & Klemp, 1982) is one of the central organizing ideas in atmospheric thermodynamics, and it is used—both explicitly and implicitly—throughout modern climate models, especially in the tropics where it works best. It stems from thermodynamics and says that a rising parcel of humid air cools more slowly than a dry parcel because cooling causes condensation of water vapor which releases latent heat that warms the parcel. Adiabatic simply means that the strict theory requires, unrealistically, that no heat enters or leaves the air parcel being modeled from the environment around it, that is, the air surrounding the parcel.
By Andy May
It came up in the comments on my last post, CERES Albedo. What is the best way to compute Earth’s albedo? The CERES data is supplied as a 1° x 1° latitude/longitude grid. It is widely accepted that Earth’s global mean albedo is around 30%. The question is then: What is the best way to estimate it using the CERES satellite data? There are two basic ways. One is to use the average solar radiation arriving at the top of the atmosphere (CERES EBAF variable “solar_mon”), which is about 340.2 W/m2 and divide that into the total solar shortwave radiation (SW) leaving (reflected from) the Earth (toa_sw_all). Using these two numbers we get an albedo of about 29%.
By Andy May
Albedo (or Earth’s global reflectivity) in this post is defined as the amount of solar shortwave (SW) radiation that the Earth reflects into space, as measured at the top of the atmosphere or TOA, divided by the total solar radiation reaching Earth also measured at the TOA. In the CERES EBAF satellite context (Loeb et al., 2009, 2018, 2021), and using their variable names, this is toa_sw_all_mon divided by solar_mon, where “mon” means monthly and “sw” means shortwave radiation. In this post we compute yearly global latitude-area-weighted means from the monthly values for most of the illustrations to avoid seasonal effects, which are very large. As seen in figure 1, there is a distinct albedo peak that falls roughly between 2004 and 2007 and afterward the albedo falls until 2025, with a second smaller, but still dramatic peak in 2020.
By Andy May
This is the text of a talk I gave on a Tom Nelson podcast. To listen to the talk and see Tom’s interview of me go here.
Some believe that CO2 and other greenhouse gas infrared emissions are as effective at increasing ocean heat content (or OHC) as solar radiation. Some even think greenhouse gas (abbreviated “GHG”) radiation is more effective than solar. There are many generally agreed points that dispute this conjecture:
Continue reading “Earth Energy Imbalance: The Sun versus CO2”By Andy May
This is an updated version of this post; the original post had incorrect figures as a result of a bug in my R program. The conclusions remain the same, but the figures and the text have changed (May 4, 2026).
The NCAR CERES EBAF satellite dataset has been adjusted to match upper ocean heat content changes. Thus, the EEI (Earth Energy Imbalance) from CERES EBAF (“Clouds and Earth’s Radiant Energy Systems, Energy Balanced and Filled”) is not estimated directly from satellite measurements. If upper ocean heat content were known accurately over a sufficiently long period, this would be fine, but it isn’t.
By Andy May
Fasullo & Trenberth (2008) build a closed, observation‑based annual energy budget for Earth’s climate system, partitioned into the top of the atmosphere (TOA), atmosphere, land, and ocean. They combine satellite radiation measurements, weather reanalyses, a stand‑alone land model, and several ocean temperature products. Over the oceans, they diagnose the net surface flux as a residual of the TOA and atmospheric budgets and compare it to independently derived ocean heat content and its trend.
By Andy May
Frank Stefani, of the Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics, has published a very interesting new paper that compares the solar “aa” index and CO2 emissions to global SST (sea surface temperatures using the HadSST4.2 dataset) and finds a CO2 sensitivity (TCR or the “Transient Climate Response”) of 1.1 to 1.4K. This is at the low end of the IPCC TCR range of 1.2 to 2.4K (IPCC, 2021, p. 93), but quite close to the values calculated by Lewis and Curry and Nicola Scafetta (Lewis & Curry, 2018), (Scafetta, 2023), and (Lewis, 2023). Scafetta found a plausible range of TCR (versus HadSST4.2) of 1.0K to 1.2K and Lewis & Curry report a range of 0.9K to 1.7K for TCR versus HadCRUT4. The estimates are compared in Table 1.
By Andy May
My previous post was a discussion about an important paper by Elizabeth Wong and Peter Minnett. The paper discusses the interaction between the thermal (or electromagnetic) skin layer (TSL) on the ocean and the bulk ocean. The TSL is only about 10 microns thick on average, although the thickness and temperature profile through it and under it changes throughout the day and night. Virtually all greenhouse gas (GHG) infrared radiation (IR) is absorbed in the TSL, whereas over 99% of solar shortwave radiation (SW) passes right through it and is absorbed deeper in the ocean (the “bulk ocean”) in the tropics under clear skies (Wong & Minnett, 2018).
By Andy May
Solar radiation penetrates oceans to depths of 10-100 meters (depending on wavelength and water clarity), directly heating the ocean mixed layer. Greenhouse gas (GHG) infrared (IR), being longwave, is absorbed in the top ~10 microns (the thermal or electromagnetic skin layer or “TSL”), where it influences temperature gradients, evaporation, and conduction. The TSL lies on top of the mixed layer and has a different temperature. Below the TSL, especially in the daytime or in the presence of very light winds, there can develop a temperature gradient between it and the “foundation” temperature or the mixed layer temperature (see figure 1). The vertically nearly constant mixed layer temperature is maintained by turbulence and convection and follows overlying air temperature trends (although not the actual air temperature) by a few days to a few weeks, or even longer, depending upon the season and latitude. Higher latitudes respond slower and lower latitudes quicker; wind speed has a large effect on the lag.
