Ideas and perspectives: Sensing energy and matter fluxes in a biota-dominated Patagonian landscape through environmental seismology – introducing the Pumalín Critical Zone Observatory Biogeosciences DOI 10.5194/bg-21-1583-2024 15 March 2024 Coastal temperate rainforests, among Earth’s carbon richest biomes, are systematically underrepresented in the global network of critical zone observatories (CZOs). Introducing here a first CZO in the heart of the Patagonian rainforest, Chile, we investigate carbon sink functioning, biota-driven landscape evolution, fluxes of matter and energy, and disturbance regimes. We invite the community to join us in cross-disciplinary collaboration to advance science in this particular environment. Read more
Hemispherically symmetric strategies for stratospheric aerosol injection Earth System Dynamics DOI 10.5194/esd-15-191-2024 13 March 2024 Injecting SO2 into the lower stratosphere can temporarily reduce global mean temperature and mitigate some risks associated with climate change, but injecting it at different latitudes and seasons would have different impacts. This study introduces new stratospheric aerosol injection (SAI) strategies and explores the importance of the choice of SAI strategy, demonstrating that it notably affects the distribution of aerosol cloud, injection efficiency, and various surface climate impacts. Read more
Regime shifts in Arctic terrestrial hydrology manifested from impacts of climate warming The Cryosphere DOI 10.5194/tc-18-1033-2024 6 March 2024 Flows of water, carbon, and materials by Arctic rivers are being altered by climate warming. We used simulations from a permafrost hydrology model to investigate future changes in quantities influencing river exports. By 2100 Arctic rivers will receive more runoff from the far north where abundant soil carbon can leach in. More water will enter them via subsurface pathways particularly in summer and autumn. An enhanced water cycle and permafrost thaw are changing river flows to coastal areas. Read more
A global compilation of diatom silica oxygen isotope records from lake sediment – trends and implications for climate reconstruction Climate of the Past DOI 10.5194/cp-20-363-2024 26 February 2024 This paper presents the first comprehensive compilation of diatom oxygen isotope records in lake sediments (δ18OBSi), supported by lake basin parameters. We infer the spatial and temporal coverage of δ18OBSi records and discuss common hemispheric trends on centennial and millennial timescales. Key results are common patterns for hydrologically open lakes in Northern Hemisphere extratropical regions during the Holocene corresponding to known climatic epochs, i.e. the Holocene Thermal Maximum. Read more
Explaining the green volcanic sunsets after the 1883 eruption of Krakatoa Atmospheric Chemistry and Physics DOI 10.5194/acp-24-2415-2024 23 February 2024 It is well known that volcanic eruptions strongly affect the colours of the twilight sky. Typically, volcanic eruptions lead to enhanced reddish and violet twilight colours. In rare cases, however, volcanic eruptions can also lead to green sunsets. This study provides an explanation for the occurrence of these unusual green sunsets based on simulations with a radiative transfer model. Green volcanic sunsets require a sufficient stratospheric aerosol optical depth and specific aerosol sizes. Read more
Bayesian multi-proxy reconstruction of early Eocene latitudinal temperature gradients Climate of the Past DOI 10.5194/cp-20-349-2024 21 February 2024 Large-scale palaeoclimate reconstructions are often based on sparse and unevenly sampled records, inviting potential biases. Here, we present a Bayesian hierarchical model that combines geochemical with ecological proxy data to model the latitudinal sea surface temperature gradient. Applying this model to the early Eocene climatic optimum highlights how our integrated approach can improve palaeoclimate reconstructions from datasets with limited sampling. Read more
Opinion: Aerosol remote sensing over the next 20 years Atmospheric Chemistry and Physics DOI 10.5194/acp-24-2113-2024 19 February 2024 Aerosols are small liquid or solid particles suspended in the atmosphere, including smoke, particulate pollution, dust, and sea salt. Today, we rely on satellites viewing Earth’s atmosphere to learn about these particles. Here, we speculate on the future to imagine how satellite viewing of aerosols will change. We expect more public and private satellites with greater capabilities, better ways to infer information from satellites, and merging of data with models. Read more
Detecting the human fingerprint in the summer 2022 western–central European soil drought Earth System Dynamics DOI 10.5194/esd-15-131-2024 16 February 2024 The 2022 summer was accompanied by widespread soil moisture deficits, including an unprecedented drought in Europe. Combining several observation-based estimates and models, we find that such an event has become at least 5 and 20 times more likely due to human-induced climate change in western Europe and the northern extratropics, respectively. Strong regional warming fuels soil desiccation; hence, projections indicate even more potent future droughts as we progress towards a 2 °C warmer world. Read more
Airborne lidar measurements of atmospheric CO2 column concentrations to cloud tops made during the 2017 ASCENDS/ABoVE campaign Atmospheric Measurement Techniques DOI 10.5194/amt-17-1061-2024 14 February 2024 NASA Goddard Space Flight Center has developed an integrated-path, differential absorption lidar approach to measure column-averaged atmospheric CO2 (XCO2). We demonstrated the lidar’s capability to measure XCO2 to cloud tops ,as well as to the ground, with the data from the summer 2017 airborne campaign in the US and Canada. This active remote sensing technique can provide all-sky data coverage and high-quality XCO2 measurements for future airborne science campaigns and space missions. Read more
Brief communication: Rapid acceleration of the Brunt Ice Shelf after calving of iceberg A-81 The Cryosphere DOI 10.5194/tc-18-705-2024 12 February 2024 The Brunt Ice Shelf has accelerated rapidly after calving an iceberg in January 2023. A decade of GPS data show that the rate of acceleration in August 2023 was 30 times higher than before calving, and velocity has doubled in 6 months. Satellite velocity maps show the extent of the change. The acceleration is due to loss of contact between the ice shelf and a pinning point known as the McDonald Ice Rumples. The observations highlight how iceberg calving can directly impact ice shelves. Read more
Design and rocket deployment of a trackable pseudo-Lagrangian drifter-based meteorological probe into the Lawrence/Linwood EF4 tornado and mesocyclone on 28 May 2019 Atmospheric Measurement Techniques DOI 10.5194/amt-17-943-2024 9 February 2024 A custom lightweight, miniaturized, and trackable meteorological probe was launched by a model rocket into the inflow region of an EF4, long-tracked tornado south of Lawrence, Kansas, on 28 May 2019 and sampled tornado core flow. The rocket reached apogee at 439 m a.g.l., releasing the “pseudo-Lagrangian drifter” by parachute directly into the tornado vortex. The probe reached a three-dimensional (3D) speed of 85.1 m s−1 in the first revolution around the tornado, measured an altitude-corrected pressure deficit of −113.5 hPa at 475 m a.s.l., and sampled a tornadic updraft speed of 65.0 m s−1. The probe then transitioned to an environment exhibiting a more tilted ascent above an altitude of 4300 m a.s.l. at speeds up to 84.0 m s−1 to a maximum altitude of 11 914 m a.s.l. 1 Hz pressure, temperature, relative humidity, GPS, acceleration, gyroscope, and magnetometer data for the flight were transmitted in real time to a ground station until 10 680 m a.s.l. and the probe landed 51 km northeast of the launch position. The probe was recovered without damage, which is attributed to the pseudo-Lagrangian drifter design, and then higher-resolution and complete 10 Hz data were downloaded for the flight. This novel deployment method and design facilitate data collection in real time from within tornadoes, the mesocyclone, and downdraft without requiring the probes to be recovered or for researchers to enter the circulation to deploy equipment. Read more
An inter-comparison of approaches and frameworks to quantify irrigation from satellite data Hydrology and Earth System Sciences DOI 10.5194/hess-28-441-2024 7 February 2024 This study provides a comparison of methodologies to quantify irrigation to enhance regional irrigation estimates. To evaluate the methodologies, we compared various approaches to quantify irrigation using soil moisture, evapotranspiration, or both within a novel baseline framework, together with irrigation estimates from other studies. We show that the synergy from using two equally important components in a joint approach within a baseline framework yields better irrigation estimates. Read more
Long-term aerosol particle depolarization ratio measurements with HALO Photonics Doppler lidar Atmospheric Measurement Techniques DOI 10.5194/amt-17-921-2024 5 February 2024 This study offers a long-term overview of aerosol particle depolarization ratio at the wavelength of 1565 nm obtained from vertical profiling measurements by Halo Doppler lidars during 4 years at four different locations across Finland. Our observations support the long-term usage of Halo Doppler lidar depolarization ratio such as the detection of aerosols that may pose a safety risk for aviation. Long-range Saharan dust transport and pollen transport are also showcased here. Read more
GC Insights: Fostering transformative change for biodiversity restoration through transdisciplinary research Geoscience Communication DOI 10.5194/gc-7-57-2024 2 February 2024 The world is facing a critical issue of biodiversity loss and ecosystem degradation, despite efforts to address it. While positive steps are being taken in the adoption of comprehensive conservation policies, more effective science-for-policy approaches are necessary to foster connectivity, engage communities, and promote transformative change. This study outlines how scientists can drive impactful change within and beyond their communities to contribute to meeting global biodiversity targets. Read more
Influence of cohesive clay on wave–current ripple dynamics captured in a 3D phase diagram Earth Surface Dynamics DOI 10.5194/esurf-12-231-2024 19 January 2024 The seabed can change its shape from flat to undulating, known as ripples; the change rate depends on whether the bed is composed of sticky mud. This study, based on experiments, shows a strong reduction in ripple size when the initial mud content is over 10.6 %. This could help geologists better interpret ancient sea conditions. We present a new model to predict ripple size by considering sticky mud. It should help engineers to describe the behaviour of the seabed when sticky mud is present. Read more
Future water storage changes over the Mediterranean, Middle East, and North Africa in response to global warming and stratospheric aerosol intervention Earth System Dynamics DOI 10.5194/esd-15-91-2024 17 January 2024 Water storage (WS) plays a profound role in the lives of people in the Middle East and North Africa as well as Mediterranean climate “hot spots”. WS change by greenhouse gas (GHG) warming is simulated with and without stratospheric aerosol intervention (SAI). WS significantly increases in the Arabian Peninsula and decreases around the Mediterranean under GHG. While SAI partially ameliorates GHG impacts, projected WS increases in dry regions and decreases in wet areas relative to present climate. Read more
GPROF V7 and beyond: assessment of current and potential future versions of the GPROF passive microwave precipitation retrievals against ground radar measurements over the continental US and the Pacific Ocean Atmospheric Measurement Techniques DOI 10.5194/amt-17-515-2024 15 January 2024 The latest version of the GPROF retrieval algorithm that produces global precipitation estimates using observations from the Global Precipitation Measurement mission is validated against ground-based radars. The validation shows that the algorithm accurately estimates precipitation on scales ranging from continental to regional. In addition, we validate candidates for the next version of the algorithm and identify principal challenges for further improving space-borne rain measurements. Read more
High-resolution spatial patterns and drivers of terrestrial ecosystem carbon dioxide, methane, and nitrous oxide fluxes in the tundra Biogeosciences DOI 10.5194/bg-21-335-2024 12 January 2024 Arctic greenhouse gas (GHG) fluxes of CO2, CH4, and N2O are important for climate feedbacks. We combined extensive in situ measurements and remote sensing data to develop machine-learning models to predict GHG fluxes at a 2 m resolution across a tundra landscape. The analysis revealed that the system was a net GHG sink and showed widespread CH4 uptake in upland vegetation types, almost surpassing the high wetland CH4 emissions at the landscape scale. Read more
Toward generalized Milankovitch theory (GMT) Climate of the Past DOI 10.5194/cp-20-151-2024 10 January 2024 Despite significant progress in modelling Quaternary climate dynamics, a comprehensive theory of glacial cycles is still lacking. Here, using the results of model simulations and data analysis, I present a framework of the generalized Milankovitch theory (GMT), which further advances the concept proposed by Milutin Milankovitch over a century ago. The theory explains a number of facts which were not known during Milankovitch time’s, such as the 100 kyr periodicity of the late Quaternary. Read more
The additionality problem of ocean alkalinity enhancement Biogeosciences DOI 10.5194/bg-21-261-2024 8 January 2024 Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities. Read more