Abstract

Although artificial intelligence (AI) models are increasingly applied to tropical cyclone (TC) intensity prediction, they predominantly rely on instantaneous meteorological variables (e.g., satellite infrared images) while often overlooking more informative temporal evolution signals, such as convective diurnal variation. The diurnal pulse (DP), a daily-scale expansion of TC upper-level cold clouds, effectively captures the spatiotemporal evolution of TC convection and is tightly linked to TC intensity changes, particularly rapid intensification (RI). By incorporating the DP as a temporal evolution signal, AI models achieved significantly improved prediction skill for TC intensification rates and RI probabilities, outperforming those using only conventional instantaneous convective indicators. Permutation tests further confirm that the DP predictors contribute more pronouncedly to forecast skill than instantaneous convective proxies. These findings highlight the untapped potential of incorporating physics-informed, continuous temporal evolution variables into AI models to improve TC intensity forecasting, especially for challenging RI events.

Abstract

Climate change alters the frequency and intensity of wildfires, but its impact on the seasonal patterns of wildfires remains underexplored. Here, we quantify historical changes in wildfire seasonality across different ecoregions in North America and assess how climate change may affect these seasonal patterns. Our study finds that boreal and taiga forests have experienced a clear advance in seasonal wildfire activity, whereas Mediterranean and desert regions show delayed and extended late-season burning. Prairie and humid forest regions exhibit comparatively muted change. Attribution analysis shows that atmospheric dryness is the dominant control, while antecedent temperature, precipitation, and soil moisture indirectly shape wildfire risk through vegetation and fuel continuity at different lag times. These findings provide a basis for interpreting future region-specific changes in wildfire seasonality and emphasize the need for region-specific assessments of future wildfire activity.

Abstract

Terpenoids play a significant role in the formation of tropospheric ozone and secondary organic aerosol. While terpenoids are largely attributed to biogenic sources, they are also widely used in consumer products that end up in the atmosphere. Terpenoid mixing ratios are reported here from samples collected during the Los Angeles (LA) Air Quality Campaign (LAAQC) in 2022 and were compared with data from three other campaigns in the LA Basin conducted between 2010 and 2021. Across all campaigns, differences in diurnal mixing ratios and composition suggest anthropogenic sources are predominant contributors to terpenoid mixing ratios in the evening to early morning (22:00–6:00 PDT), shifting to predominately biogenic sources in the afternoon (10:00–18:00 PDT). This manuscript presents the first evidence for a significant presence of anthropogenic terpenoids in the LA Basin and highlights the need for systematically studying anthropogenic and biogenic terpenoid emissions in urban areas.

Abstract

Radiative-convective equilibrium (RCE) is commonly used as an approximation of the time- and space-averaged tropical atmosphere. We examine two reanalyses to assess the extent to which column-integrated radiative cooling balances convective heating (“bulk RCE”) in the tropics and at higher latitudes. Our analysis shows that bulk RCE is a reasonable approximation of the tropics over ocean, but not land. Surprisingly, bulk RCE is often a reasonable approximation in mid-latitudes, especially over land. These findings are explained by a simple argument. Over land, the ground heat flux is small, and bulk RCE arises when the top-of-atmosphere net radiative flux is small, which occurs in mid-latitudes. Over ocean, the same mechanism applies but the ocean heat flux can be substantial and causes deviations relative to land. We conclude that bulk RCE is a surprisingly useful approximation of mid-latitude land climate, which permits the development of simple theory for land climate, more broadly.

Abstract

Under accelerating climate change, variations in global desert area remain uncertain, with estimates differing by more than a factor of two. Here, we present the first 40-year global mapping of desert area changes at 30 m resolution using Landsat imagery, achieving a classification accuracy of 92%. Our results show that global desert area exhibited a declining trend during 1985–2024, at a rate of −2.27 × 104 km2 yr−1, largely driven by decreases in Australia, East Asia, Central Asia, and South Africa. Desert area variations reflect the balance among water supply, soil moisture, and atmospheric demand. Our analysis indicates that episodic increases in water inputs, together with vegetation buffering, enhanced effective water availability, which coincided with global desert contraction. Human activities influence East Asian desert changes, whereas global desert changes reflect the combined effects of human activities and climatic factors. Climatic factors may play a primary role in driving desert variations.

Abstract

Widespread aeolian loess-paleosol and red clay sediments on the Chinese Loess Plateau (CLP) provide a globally unique terrestrial archive of Neogene–Quaternary climate. However, the timing and associated mechanisms of red clay to loess-paleosol shift remain debated. Here we present new magnetostratigraphic and environmental magnetic results from the Baode section, northeastern CLP. Magnetostratigraphic result demonstrates that this section spans from the upper Gilbert to lower Matuyama Chrons (3.6–2.0 Ma). Red clay shifted to loess-paleosol sequence at ∼2.7 Ma, synchronous with the intensification of Northern Hemisphere glaciation (iNHG). Rock magnetic data indicate dominance of fine pedogenic magnetic grains, with higher concentrations in red clay. The continuous magnetic susceptibility record suggests decreases in pedogenic magnetic population and precipitation at ∼2.7 Ma. We propose that ice-sheet expansion across the iNHG, coupled with declining CO2, triggered the onset of loess-paleosol accumulation on the CLP by suppressing Asian summer monsoon while enhancing winter monsoon circulation and inland aridity.

Abstract

Solar energy is central to decarbonization and national energy plans, yet its deployment is limited by gaps in understanding how solar irradiance varies in space and time. We present the first continent-scale, sub-daily analysis of solar resource variability using Himawari-8/9 satellite data for Australia's renewable energy zones. We apply metrics capturing average irradiance, persistence, and spatial synchrony of cloudy conditions. Southern Australia experiences persistent low irradiance events in the winter but show limited seasonality in cloud cover. Convectively driven short events occur in the north, and inland regions are generally more resilient than coastal zones. Midday is consistently the clearest period, but correlations across southeastern zones increase the risk of simultaneous generation deficits. These results highlight the importance of accounting for both local variability and inter-regional connectivity, providing a framework to better leverage Australia's solar resources, enhance system reliability, and support solar PV integration into a decarbonized power system.

Abstract

Throughout the Solar System, volatiles are found as solid ices. Returning ices to Earth for scientific analysis is critical to understanding the formation of a Solar System that bears life. This challenge begins with the Artemis missions to the lunar south polar region, where the coldest lunar regolith is enriched in H2O and other ices—systems with complex phase equilibria. Ignoring solution chemistry results in erroneous conclusions that—if allowed to guide Artemis sampling, transport, and curation planning—would result in irreparable damage to returned samples. Here we use the H2O-NH3 binary as a model for more complex ices. At 1 bar, H2O-rich ices undergo peritectic melting at or below −95°C, changing the textural record of the ice and generating a liquid with >30% NH3. At lunar surface pressures, sublimation of NH3—and sample damage—begins at least 100 C° lower, increasing the challenge of icy sample return.

Abstract

As Arctic warming accelerates, understanding hydroclimate shifts is key to projecting glacier melt and sea-level rise. We assess the climatic signature of the Little Ice Age (LIA; ∼1250 to 1900) by quantifying changes in equilibrium-line altitude (ΔELA) for 215 Alaskan glaciers from the LIA maximum to present (2016–2024), using remote sensing and geographic information system methods. ELAs have risen by 170 ± 8 m, equivalent to 1.6 ± 0.3°C summer warming (assuming constant precipitation) or 248 ± 89 mm w.e. annual precipitation increase (assuming 2.3°C warming). The latter is ∼4X the precipitation change observed since 1950. Glacier morphology and topographic setting explain 32% of ΔELA variance, likely reflecting differing sensitivities to climatic shifts and elevation-dependent warming. Spatially interpolated ΔELA residuals are most strongly correlated to winter precipitation (r = −0.67). Results suggest the LIA was characterized by (a) colder, drier conditions and (b) a weak, westward-displaced Aleutian Low that has since strengthened and shifted eastward.

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The Australian government proposed on Friday setting up a A$3.9 billion ($2.8 billion) fund for water infrastructure and drought related projects to buffer farming communities from future droughts, as parts of the country endure extreme dry conditions.