By Andy May
I first read about Deployable Energy on Joanne Nova’s website and was very interested in their innovative small modular nuclear reactor and how it worked. The reactor was produced under President Trump’s 2025 nuclear reactor plan. It was designed by Australian Bobby Gallagher and his team in Houston. It can produce one megawatt of power, at a cost of 15 cents per kilowatt hour, for five years before refueling is required. The entire reactor can fit on the bed of a Ford F150 pickup, as shown in the photo. More importantly, it can be manufactured in a factory, fits into one 20-foot shipping container, uses the existing conventional supply chain, and requires no exotic custom-made components.
Comparing Equilibrium, Kinetic, and Non-Equilibrium Temperatures
By Andy May
This is part 3 of a series on defining temperature. In part one I covered various temperature definitions used and pointed out that “temperature,” unmodified is only a measurement of an emergent statistical property with little meaning beyond that. It is important in physics and daily life, but not a primitive well defined property like mass or energy. In part two I covered kinetic temperature, which is “what we measure with a thermometer” (Schroeder, 2000). In the original X discussion that spurred me to write these posts, some argued that the “real” definition of “temperature” was the thermodynamic equilibrium temperature. Of course this is not true. For nearly everyone on Earth, thermometers measure temperature.
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Kinetic Temperature
By Andy May
In my last post, “Defining Temperature,” we saw that temperature is a simple measurement that has little meaning without context. If one is referring to the equilibrium system state variable or “thermodynamic equilibrium temperature,” they should state that to provide clarity because there are many types of temperature measurements and they mean different things. Thermodynamic equilibrium temperature is defined in the previous post. There are many definitions of temperature, I will discuss the most common ones used in physics and everyday life in this post and perhaps in subsequent posts. The fundamental meaning of thermodynamic equilibrium temperature and the temperature measured with a thermometer are very different and they should not be confused.
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Defining Temperature
By Andy May
I never thought I would participate in a serious debate on the definition of “temperature.” But it happened on twitter, and with people who have degrees in physics and other hard sciences! Since I worked with kinetic and effective temperature estimates for 42 years as a petrophysicist, I knew these topics intimately and never gave them a second thought. So, to hear people say (paraphrasing) that they were not really temperatures came as a shock. Their proposed sole definition of “temperature:” is the thermodynamic statistical definition:
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Modeling the Troposphere
By Andy May and Philip Mulholland
IGRA2 radiosonde 1991–2025 means (10 hPa bins, 10° latitude slices) show systematic differences between observed mid-tropospheric temperatures, and the CMIP 5 & 6 (Coupled Model Intercomparison Project, see IPCC, 2021) ensemble means as shown by McKitrick & Christy (2020) and Po-Chedley et al. (2022). The difference between the CMIP models and the observations is most noticeable in the tropics as discussed here. While multiple reasons, such as too much weight on the warming effect of additional CO2, anomalous cloud feedback, or bad weather balloon data, have been proposed (IPCC, 2021, p. 443), no one really knows why they are so poor at reproducing tropospheric temperature profiles.
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Testing the Dew-Point Anchor Hypothesis
By Andy May and Philip Mulholland
Earlier this year Philip Mulholland published the details of his Dew-Point Anchor Hypothesis or “DPAH” (Mulholland P. , 2026a). The hypothesis assumes that the Dew-Point Lifting Condensation Level (LCL), as calculated from surface conditions in the tropics, can act as an anchor for the lower and middle troposphere. This idea moves the independent variable in climate modeling from the radiative balance at the top of the atmosphere (TOA), to the cloud level inside the troposphere.
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Do Los Niños cause climatic cooling?
By Andy May
This post is available in German, courtesy of Christian Freuer, if you prefer that language. See here.
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.
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The Moist-Adiabatic Theory vs. Reality
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.
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Calculating Earth’s Albedo, Part 2
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%.
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CERES Albedo
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.
