Cloud phase estimation and macrophysical properties of low-level clouds using in-situ and radar measurements over the Southern Ocean during the SOCRATES campaign
Anik Das, Baike Xi, Xiaojian Zheng, and Xiquan Dong
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-124,2024
Preprint under review for AMT (discussion: open, 0 comments)
Understanding the cloud phase and macrophysical properties of Southern Ocean clouds is crucial to enhancing our understanding of the region. The cloud radar and in-situ probes during the SOCRATES aircraft campaign are used to develop a new method to determine cloud boundaries and dominant phase. Low clouds (<3km) are found to be the most dominant cloud type (~90%), with liquid being the most dominant phase type, followed by ice and mixed with a greater incidence of drizzle around the cloud base.
Cloud masks and cloud type classification using EarthCARE CPR and ATLID
Hajime Okamoto, Kaori Sato, Tomoaki Nishizawa, Yoshitaka Jin, Shota Ogawa, Hiroshi Ishimoto, Yuichiro Hagihara, EIji Oikawa, Maki Kikuchi, Masaki Satoh, and Wooosub Roh
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-103,2024
Preprint under review for AMT (discussion: open, 0 comments)
The article gives the descriptions of the Japan Aerospace Exploration Agency (JAXA) level 2 (L2) cloud mask and cloud particle type algorithms for CPR and ATLID onboard Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) satellite. The 355nm-multiple scattering polarization lidar was used to develop ATLID algorithm. Evaluations show the agreements for CPR-only, ATLID-only and CPR-ATLID synergy algorithms to be about 80%, 85% and 80%, respectively on average for about two EarthCARE orbits.
Abstract
The East African Rift System (EARS) provides an opportunity to constrain the relationship between magmatism and plate thinning. During continental rifting, magmatism is often considered a derivative of strain accommodation—as the continental plate thins, decompression melting of the upper mantle occurs. The Turkana Depression preserves among the most extensive Cenozoic magmatic record in the rift. This magmatic record, which comprises distinct basaltic pulses followed by periods of relative magmatic quiescence, is perplexing given the lack of evidence for temporal heterogeneity in the thermo-chemical state of the upper mantle, the nonexistence of lithospheric delamination related fast-wave speed anomalies in the upper mantle, and the absence of evidence for sudden, accelerated divergence of Nubia and Somalia. We focus on the Pliocene Gombe Stratoid Series and show how lithospheric thinning may result in pulsed magma generation from a plume-influenced mantle. By solving the 1D advection-diffusion equation using rates of plate thinning broadly equivalent to those measured geodetically today we show that despite elevated mantle potential temperature, melt generation may not occur and thereby result in extended intervals of quiescence. By contrast, an increase in the rate of plate thinning can generate magma volumes that are on the order of that estimated for the parental magma of the Gombe Stratoid Series. The coincidence of large-volume stratiform basalt events within the East African Rift shortly before the development of axial zones of tectonic-magmatic activity suggests that the plate thinning needed to form these stratiform basalts may herald the onset of the localization of strain.
Flood relief logistics planning for coastal cities: a case study in Shanghai, China
Pujun Liang, Jie Yin, Dandan Wang, Yi Lu, Yuhan Yang, Dan Gao, and Jianfeng Mai
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-88,2024
Preprint under review for NHESS (discussion: open, 1 comment)
Addressing coastal city flood risks, this article examines relief logistics planning, employing a GIS-network analysis and optimization model to minimize costs and dissatisfaction. The investigation, grounded in Shanghai's emergency infrastructure and flood relief logistics framework, presents feasible distribution strategies. Meanwhile, the case study indicates that the supply levels of Emergency Flood Shelters and Emergency Reserve Warehouses vary in different coastal flood scenarios.
Abstract
In this study, we use multi-instrument observations (all-sky imager (ASI), global navigation satellite system (GPS) receivers, digisonde) to study the interaction of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) on 13 November 2018. The most attractive aspect of this event is that the interaction appeared between two dark bands both propagated southwestward. The airglow observations show that the latter band moved faster and caught up with the former, and these two bands merged into a new one. The propagating characteristics and morphology of the MSTIDs changed during the interaction process. The simulations from the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) suggested that the ionospheric background zonal winds and electron density distributions could play essential roles in the interaction of the MSTIDs. Moreover, the merging process might be associated with the electrostatic reconnection.
Abstract
Wave particle interactions are very important to understand the intricate evolution of the Earth's radiation belt electrons. Kinetic simulations, in terms of solving the Fokker-Planck equation based on the quasilinear theory, are usually used to simulate the radiation belt electron dynamic evolution. However, the global wave and plasma density distributions adopted in the kinetic simulations are very difficult to be directly obtained by satellites. Here we present a new model, by integrating the machine learning technique and kinetic simulations, to analyze the spatiotemporal evolution of radiation belt electrons scattered by lower band chorus (LBC). Compared to the observations, our integrated model produces effectively the global distribution of plasmapause location, plasma density, and LBC intensity, and assesses quantitatively the scattering effect driven by LBC waves at different magnetic local times (MLT), L-shell (the Mcllwain L-parameter), and time. Incorporating the effect of radiation electron drift, we further use the 2-D Fokker-Planck equation to simulate the variations of electron phase space density in different MLT sectors at a fixed L, and find that the integrated model replicates reasonably the multi-MeV electron acceleration at L = 4.5 during the period from the main phase to the early recovery phase of the storm. Our results demonstrate that such an integrated model, on basis of a combination of the machine learning technique and kinetic simulations, provides valuable means for improved understanding of the global dynamic evolution of the Earth's radiation belt electrons.
Long-term changes in the dependence of NmF2 on solar flux at Juliusruh
Maria Gloria Tan Jun Rios, Claudia Borries, Huixin Liu, and Jens Mielich
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2024-11,2024
Preprint under review for ANGEO (discussion: open, 3 comments)
The study analyzes hourly NmF2 data from Juliusruh (1957 to 2023) and examines the response of NmF2 to solar flux by using three different solar EUV proxies for six solar cycles, including a separation of the ascending and descending phases. The response is better represented with a quadratic regression and F30 shows the highest correlation for describing NmF2 dependence over time. These results revealed a steady decrease in NmF2, influenced by the intensity of the solar activity index.
Abstract
Previous simulations have suggested that O+ outflow plays a role in driving the sawtooth oscillations. This study investigates the role of O+ by identifying the differences in ionospheric outflow between sawtooth and non-sawtooth storms using 11 years of FAST/Time of flight Energy Angle Mass Spectrograph (TEAMS) ion composition data from 1996 through 2007 during storms driven by coronal mass ejections. We find that the storm's initial phase shows larger O+ outflow during non-sawtooth storms, and the main and recovery phases revealed differences in the location of ionospheric outflow. On the pre-midnight sector, a larger O+ outflow was observed during the main phase of sawtooth storms, while non-sawtooth storms exhibited stronger O+ outflow during the recovery phase. On the dayside, the peak outflow shifts significantly toward dawn during sawtooth storms. This strong dawnside sector outflow during sawtooth storms warrants consideration.
Abstract
This study reports coordinated observation of ionospheric irregularities from VHF Radar, GPS and IRNSS (Indian Regional Navigation Satellite System), from regions near the northern crest of the EIA (Equatorial Ionization Anomaly), which has not been explored earlier. Efforts have been made to study the signal-in-space environment for concurrent detection of ionospheric irregularities over a range of radio frequency, starting from 53 MHz of the Radar, to L-band of GPS at 1,575.42 MHz and S band signal of IRNSS at 2,492.5 MHz. The radar is operational at Ionosphere Field Station, Haringhata (geographic latitude 22.93°N; geographic longitude 88.51°E; magnetic dip angle 36.2°N) of University of Calcutta. The GPS and IRNSS data are recorded at Calcutta (22.58°N, 88.38°E geographic; magnetic dip: 36°N), separated from Haringhata by 50 km. The spatial as well as temporal variations of irregularities affecting different radio frequencies have been presented. Coordinated observations have been made during period of March–April 2023. Results of the study reveal the common zone of impact of the different radio frequency links spanning from 53 to 2,592.5 MHz and was identified within 16°–25°N, 85°–90°E. During coordinated observations made over several days, irregularity structures have been observed with radar, having backscatter SNR (Signal to Noise ratio) intensity within −5 to 15 dB. During this time, while intense L band scintillation was recorded on multiple satellites of GPS, scintillation recorded at S band signal was moderate to intense.
Abstract
Debris flows and floods generated by rainfall runoff occur in rocky mountainous landscapes and burned steeplands. Flow type is commonly identified post-event through interpretation of depositional structures, but these may be poorly preserved or misinterpreted. Prior research indicates that discharge magnitude is commonly amplified in debris flows relative to floods due to volumetric bulking and increased frictional resistance. Here, we use this flow amplification to develop a metric (Q*) to separate debris flows from floods based on the ratio of observed peak discharge to the theoretical maximum water discharge from rainfall runoff. We compile 642 observations of floods and debris flows and demonstrate that Q* distinguishes flow type to ∼92% accuracy. Q* allows for accurate identification of debris flows through simple channel cross-section surveys rather than through qualitative interpretation of deposits, and therefore should increase the performance of models and engineered structures that require accurate flow-type observations.
Abstract
The Southern Alps experiences rapid bedrock uplift and intense surface processes like erosion and deglaciation. We quantify how the erosion and deglaciation contribute to the ongoing vertical motions using geophysical models. The erosional unloading uplift is found to be 0.5–1.5 mm/yr throughout the central Southern Alps, whereas the recent deglaciation may locally produce uplift up to 1–3 mm/yr. The estimated unloading uplift accounts for 10%–40% of the GNSS-observed uplift. After correcting the unloading uplift, the GNSS-observed uplift can be explained by about 4–6 mm/yr dip-slip motion on the Alpine fault, which is 10%–50% below previous geodetic estimates. Hence, unloading uplift must be evaluated when interpreting geodetic observations in tectonically active mountain ranges subjected to intense surface processes.
Abstract
Understanding the key drivers controlling rainfall stable isotope variations in inland tropical regions remains a global challenge. We present novel high-frequency isotope data (5–30 min intervals) to disentangle the evolution of six stratiform rainfall events (N = 112) during the passage of convective systems in inland Brazil (September 2019–June 2020). These systems produced stratiform rainfall of variable cloud features. Depleted stratiform events (δ18Oinitial ≤ −4.2‰ and δ18Omean ≤ −6.1‰) were characterized by cooler cloud-top temperatures (≤−38°C), larger areas (≥48 km2), higher liquid-ice ratios (≥3.1), and higher melting layer heights (≥3.8 km), compared to enriched stratiform events (δ18Oinitial ≥ −3.8‰ and δ18Omean ≥ −5.1‰). Cloud vertical structure variability was reflected in a wide range of δ18O temporal patterns and abrupt shifts in d-excess. Our findings provide a new perspective to the ongoing debate about isotopic variability and the partitioning of rainfall types across the tropics.
Implementation and assessment of a model including mixotrophs and the carbonate cycle (Eco3M_MIX-CarbOx v1.0) in a highly dynamic Mediterranean coastal environment (Bay of Marseille, France) – Part 2: Towards a better representation of total alkalinity when modeling the carbonate system and air–sea CO2 fluxes
Lucille Barré, Frédéric Diaz, Thibaut Wagener, Camille Mazoyer, Christophe Yohia, and Christel Pinazo
Geosci. Model Dev., 17, 5851–5882, https://doi.org/10.5194/gmd-17-5851-2024, 2024
The carbonate system is typically studied using measurements, but modeling can contribute valuable insights. Using a biogeochemical model, we propose a new representation of total alkalinity, dissolved inorganic carbon, pCO2, and pH in a highly dynamic Mediterranean coastal area, the Bay of Marseille, a useful addition to measurements. Through a detailed analysis of pCO2 and air–sea CO2 fluxes, we show that variations are strongly impacted by the hydrodynamic processes that affect the bay.
Updating the radiation infrastructure in MESSy (based on MESSy version 2.55)
Matthias Nützel, Laura Stecher, Patrick Jöckel, Franziska Winterstein, Martin Dameris, Michael Ponater, Phoebe Graf, and Markus Kunze
Geosci. Model Dev., 17, 5821–5849, https://doi.org/10.5194/gmd-17-5821-2024, 2024
We extended the infrastructure of our modelling system to enable the use of an additional radiation scheme. After calibrating the model setups to the old and the new radiation scheme, we find that the simulation with the new scheme shows considerable improvements, e.g. concerning the cold-point temperature and stratospheric water vapour. Furthermore, perturbations of radiative fluxes associated with greenhouse gas changes, e.g. of methane, tend to be improved when the new scheme is employed.
“Pochva”: a new hydro-thermal process model in soil, snow, vegetation for application in atmosphere numerical models
Oxana Drofa
Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2024-138,2024
Preprint under review for GMD (discussion: open, 0 comments)
This paper presents the result of many years of efforts of the author, who developed an original mathematical numerical model of heat and moisture exchange processes in soil, vegetation, snow. The author relied on her 30 years of research experience in atmospheric numerical modelling. The presented model is the fruit of research on physical processes at the surface-atmosphere interface and their numerical approximation and aims at improving numerical weather forecasting and climate simulations.
Abstract
The formation of Lau Basin records an extreme event of plate tectonics, with the associated Tonga trench exhibiting the fastest retreat in the world (16 cm/yr). Yet paleogeographic reconstructions suggest that seafloor spreading in the Lau Basin only initiated around 6 Ma. This kinematics is difficult to reconcile with our present understanding of how subduction drives plate motions. Using numerical models, we propose that eastward migration of the Lau Ridge concurrent with trench retreat explains both the narrow width and thickened crust of the Lau Basin. To match the slab geometry and basin width along the Tonga-Kermadec trench, our models suggest that fast trench retreat rate of 16 cm/yr might start ~15 Ma. Tonga slab rollback induced vigorous mantle flow underneath the South Fiji Basin which is driving the extension and thinning of the basin and contributing to its observed deeper bathymetry compared to neighboring basins.
Abstract
The North Atlantic Oscillation (NAO) and North Atlantic tripole sea surface temperature (SST_tri) are important modes in the atmosphere and ocean over the North Atlantic, respectively. The link between the two is well-known. However, this link weakened during 1980–2001, which is particularly pronounced in late winter and was not detected in early winter. This phenomenon has not been well revealed. The role of NAO in the above correlation changes was discussed. In late winter, a significant eastward shift (up to 20° longitude) of NAO south center during 1980–2001 was observed in both observation and CMIP6, accompanied by the eastward expansion of NAO north center. Spatial shift of the NAO forced the region of strong air-sea interactions to shift and resulting in the collapse of NAO-related SST_tri. These findings deepen our understanding of the NAO on the subseasonal scale.
Abstract
The solar wind interaction with planetary magnetospheres dictates the mechanism through which energy is transported across planetary systems. The magnetohydrodynamic plasma description suggests that solar wind conditions in the outer solar system encourage the magnetopause boundaries at Uranus and Neptune to be more Kelvin-Helmholtz unstable, however, no quantitative assessment has been performed. To characterize the viscous solar wind interaction at Uranus and Neptune, we create an analytical model to determine where Kelvin-Helmholtz Instabilities (KHIs) may form along their magnetopauses by searching for regions where the minimum condition for KHI formation is satisfied. We run the model at solstice and equinox for a range of Interplanetary Magnetic Field (IMF) strengths, and rotation phases. We find minimal seasonal variation for low IMF strengths (B = 0.01 nT), with ∼70% of the magnetopause surface at Uranus and ∼80% at Neptune, enabling KHI formation. For periods of stronger IMF strength (B > 0.3 nT), KHIs were significantly suppressed. While KHIs depend on both the conditions inside the magnetopause boundary and the shocked solar wind IMF strength, we find that the IMF strength is the most significant criterion in determining whether or not KHIs are allowed to form at the magnetopause boundaries.
Abstract
Along a climate gradient in the Chilean coastal mountains, we investigated denudation rates using the meteoric cosmogenic nuclide 10Be and its ratio to stable 9Be, and chemical depletion fractions (CDFs) in bulk soil samples. We find that the fraction of 9Be released from bedrock is a sensitive indicator of weathering, similar to CDF. Meteoric 10Be decreases exponentially with depth, reflecting the reactive nature of this tracer. We also measured denudation rates by the well-understood in situ cosmogenic 10Be system on quartz. Assuming that both systems record the same denudation rate we calculated the depositional flux of meteoric 10Be for each study site. The flux agrees to that derived from atmospheric models in the mediterranean and humid areas. In contrast, in the arid and semi-arid areas, the calculated flux agrees with a precipitation-derived flux, indicating delivery of 10Be to be affected by small-scale climatic variations not reflected by current atmospheric models.
Abstract
In this paper, using a three-dimensional multifluid MHD model, we studied the effects of the interplanetary magnetic field (IMF) clock angle and the latitude position of the intense crustal magnetic field (ICMF) on the escape of ions O+, O2+ ${\mathrm{O}}_{\mathrm{2}}^{+}$, and CO2+ ${\mathrm{C}\mathrm{O}}_{\mathrm{2}}^{+}$ at Mars. The main results are as follows: (a) The IMF clock angle affects the ion escape at Mars. When the ICMF is on the dayside, the ion escape rate reaches a maximum at the IMF clock angles close to 60°–90° and a minimum at the IMF clock angles close to 120°–150°, because the ICMF can change the topology of the magnetic field and affect the interaction between the solar wind and Mars. The difference between the maximum and minimum ion escape rates due to the IMF clock angle can reach over 50%. (b) Compared with the −ESW hemisphere, the escape flux of O2+ ${\mathrm{O}}_{\mathrm{2}}^{+}$ and CO2+ ${\mathrm{C}\mathrm{O}}_{\mathrm{2}}^{+}$ in the +ESW hemisphere is more significant. However, O+ generally has a larger escape flux in the −ESW hemisphere. The different results in the ±ESW hemispheres might be due to the larger distribution of the hot oxygen corona, which changes the flow pattern of O+. (c) The latitude location of the ICMF can also affect the ion escape. When the ICMF is on the dayside, as the subsolar point varies from 25°S to 25°N, that is, the intense crustal magnetic field position keeps shifting southward, the ion escape rate shows a gradual increase.
