Mechanisms of Convective Clustering During a 2‐Day Rain Event in AMIE/DYNAMO
Not Available
54 ENVIRONMENTAL SCIENCES↗
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Results for “rain”
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Coupling Warm Rain With an Eddy Diffusivity/Mass Flux Parameterization: 1. Model Description and Validation
A new version of the stochastic multiplume Jet Propulsion Laboratory Eddy-Diffusivity/Mass-Flux (JPL-EDMF) parameterization which consistently couples the simplified Khairoutdinov and Kogan (2000), https://doi.org/10.1175/1520-0493(2000)128<0229:ANCPPI>2.0.CO;2, warm phase cloud microphysical parameterization with the parameterization of cloud macrophysical and subgrid scale dynamical processes is described. The new parameterization combines the EDMF approach with an assumed shape of a joint probability density function of thermodynamic and kinematic variables which provide the basis for the computation of all parameterized processes. As far as we are aware this is the first attempt to consistently couple all of these parameterized processes in the EDMF framework. This paper is part one of a two paper series. Here, the JPL-EDMF parameterization is described and benchmark simulations of precipitating stratocumulus and cumulus convection are performed in a single-column-model framework. The parameterization results compare favorably to the reference large-eddy-simulation results. In the second part (Smalley et al., 2022, https://doi.org/10.1029/2021MS002729) the JPL-EDMF parameterization is validated for a wide range of observation-based scenarios covering the continuous transition from subtropical stratocumulus to cumulus convection derived from global reanalysis, and parameterization uncertainties are studied in detail.
54 ENVIRONMENTAL SCIENCES↗
Data-Driven Reduced Ordering Modeling for Warm Rain Microphysics
Explore the source record for details and available documents.
Computer science↗
Fog and rain in the Amazon
Significance We here demonstrate that we can resolve the seasonality of the hydrologic cycle in the Amazon using an approach, opposite to general circulation models, in which we resolve convection and parameterize large-scale circulation as a function of the resolved convection. The results emphasize the key role of cloud albedo feedback and, in particular, of the morning fog layer in determining the diurnal course of surface heat fluxes and seasonality of the surface and atmospheric heat and water cycles. These results indicate that our understanding of tropical climates over land can be considerably advanced by using coupled land−atmosphere models with explicit convection and parameterized large-scale dynamics.
54 ENVIRONMENTAL SCIENCES↗
Shower thoughts: why scientists should spend more time in the rain
Abstract Stormwater is a vital resource and dynamic driver of terrestrial ecosystem processes. However, processes controlling interactions during and shortly after storms are often poorly seen and poorly sensed when direct observations are substituted with technological ones. We discuss how human observations complement technological ones and the benefits of scientists spending more time in the storm. Human observation can reveal ephemeral storm-related phenomena such as biogeochemical hot moments, organismal responses, and sedimentary processes that can then be explored in greater resolution using sensors and virtual experiments. Storm-related phenomena trigger lasting, oversized impacts on hydrologic and biogeochemical processes, organismal traits or functions, and ecosystem services at all scales. We provide examples of phenomena in forests, across disciplines and scales, that have been overlooked in past research to inspire mindful, holistic observation of ecosystems during storms. We conclude that technological observations alone are insufficient to trace the process complexity and unpredictability of fleeting biogeochemical or ecological events without the shower thoughts produced by scientists’ human sensory and cognitive systems during storms.
ecosystem functioning↗
Reducing the aerosol forcing uncertainty using observational constraints on warm rain processes
Global climate models (GCMs) disagree with other lines of evidence on the rapid adjustments of cloud cover and liquid water path to anthropogenic aerosols. Attempts to use observations to constrain the parameterizations of cloud processes in GCMs have failed to reduce the disagreement. We propose using observations sensitive to the relevant cloud processes rather than only to the atmospheric state and focusing on process realism in the absence of aerosol perturbations in addition to the process susceptibility to aerosols. We show that process-sensitive observations of precipitation can reduce the uncertainty on GCM estimates of rapid cloud adjustments to aerosols. The feasibility of an observational constraint depends on understanding the precipitation intensity spectrum in both observations and models and also on improving methods to compare the two.
54 ENVIRONMENTAL SCIENCES↗
Did the exposure of coacervate droplets to rain make them the first stable protocells?
Membraneless coacervate microdroplets have long been proposed as model protocells as they can grow, divide, and concentrate RNA by natural partitioning. However, the rapid exchange of RNA between these compartments, along with their rapid fusion, both within minutes, means that individual droplets would be unable to maintain their separate genetic identities. Hence, Darwinian evolution would not be possible, and the population would be vulnerable to collapse due to the rapid spread of parasitic RNAs. In this study, we show that distilled water, mimicking rain/freshwater, leads to the formation of electrostatic crosslinks on the interface of coacervate droplets that not only suppress droplet fusion indefinitely but also allow the spatiotemporal compartmentalization of RNA on a timescale of days depending on the length and structure of RNA. We suggest that these nonfusing membraneless droplets could potentially act as protocells with the capacity to evolve compartmentalized ribozymes in prebiotic environments.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Diazotrophs Show Signs of Restoration in Amazon Rain Forest Soils with Ecosystem Rehabilitation
Biological nitrogen fixation can be an important source of nitrogen in tropical forests that serve as a major CO 2 sink. Extensive deforestation of the Amazon is known to influence microbial communities and the biogeochemical cycles they mediate. However, it is unknown how diazotrophs (nitrogen-fixing microorganisms) respond to deforestation and subsequent ecosystem conversion to agriculture, as well as whether they can recover in secondary forests that are established after agriculture is abandoned. To address these knowledge gaps, here we combined a spatially explicit sampling approach with high-throughput sequencing of nifH genes. The main objectives were to assess the functional distance decay relationship of the diazotrophic bacterial community in a tropical forest ecosystem and to quantify the roles of various factors that drive the observed changes in the diazotrophic community structure. We observed an increase in local diazotrophic diversity (α-diversity) with a decrease in community turnover (β-diversity), associated with a shift in diazotrophic community structure as a result of the forest-to-pasture conversion. Both diazotrophic community turnover and structure showed signs of recovery in secondary forests. Changes in the diazotrophic community were primarily driven by the change in land use rather than differences in geochemical characteristics or geographic distances. The diazotroph communities in secondary forests resembled those in primary forests, suggesting that at least partial recovery of diazotrophs is possible following agricultural abandonment. IMPORTANCE The Amazon region is a major tropical forest region that is being deforested at an alarming rate to create space for cattle ranching and agriculture. Diazotrophs (nitrogen-fixing microorganisms) play an important role in supplying soil N for plant growth in tropical forests. It is unknown how diazotrophs respond to deforestation and whether they can recover in secondary forests that establish after agriculture is abandoned. Using high-throughput sequencing of nifH genes, we characterized the response of diazotrophs’ β-diversity and identified major drivers of changes in diazotrophs from forest-to-pasture and pasture-to-secondary-forest conversions. Studying the impact of land use change on diazotrophs is important for a better understanding of the impact of deforestation on tropical forest ecosystem functioning, and our results on the potential recovery of diazotrophs in secondary forests imply the possible restoration of ecosystem functions in secondary forests.
59 BASIC BIOLOGICAL SCIENCES↗
Sensitivity of a Cumulus Parameterization Scheme to Precipitation Production Representation and Its Impact on a Heavy Rain Event over Korea
The sensitivity of a cumulus parameterization scheme (CPS) to a representation of precipitation production is examined. To do this, the parameter that determines the fraction of cloud condensate converted to precipitation in the simplified Arakawa–Schubert (SAS) convection scheme is modified following the results from a cloud-resolving simulation. While the original conversion parameter is assumed to be constant, the revised parameter includes a temperature dependency above the freezing level, whichleadstolessproductionoffrozenprecipitating condensate with height. The revised CPS has been evaluated for a heavy rainfall event over Korea as well as medium-range forecasts using the Global/Regional Integrated Model system (GRIMs). The inefficient conversion of cloud condensate to convective precipitation at colder temperatures generally leads to a decrease in pre-cipitation, especially in the category of heavy rainfall. The resultant increase of detrained moisture induces moistening and cooling at the top of clouds. A statistical evaluation of the medium-range forecasts with the revised precipitation conversion parameter shows an overall improvement of the forecast skill in precipitation and large-scale fields, indicating importance of more realistic representation of microphysical processes in CPSs.
Han, Ji-Young↗
Multidecadal stability in tropical rain forest structure and dynamics across an old-growth landscape
Not Available
54 ENVIRONMENTAL SCIENCES↗
Results of Magnesium in Rain Water Sampling
Lawrence Livermore National Laboratory (LLNL) is regulated under California's Industrial General Permit (IGP) under SIC code 4953 (Hazardous Waste Facilities). According to the IGP, facilities under this SIC code must sample for magnesium in their industrial stormwater runoff. In the 2015-2016 stormwater year, LLNL entered level 1 status for magnesium. In the 2016-2017 stormwater year, LLNL added filter inserts and filter rolls to storm-basin inlets but still exceeded the Numeric Action Level (NAL) and entered Level 2 status for magesium. LLNL's 2017 Level 2 Exceedance Response Action (ERA) technical report, demonstrated that the high magnesium levels are from natural processes occurring in the surrounding geology instead of anthropogenic or industrial activity. LLNL found the source of magnesium is caused from eroded minderal phases and likely dry deposition of air particulates (Esser, 2016). To further investigate the source of magnesium and to strengthen LLNL's conclusion that elevated magnesium concentrations are from natural sources, LLNL conducted sampling events to analyse the magnesium levels in direct rainfall.
54 ENVIRONMENTAL SCIENCES↗
Weighing Bucket Rain Gauge Instrument Handbook
The OTT precipitation gauge is used for automatic determination of the intensity and amount of precipitation. In contrast to conventional precipitation gauges, the Pluvio2 works using the balance principle. The gauge reliably recognizes precipitation by determining the weight of the collecting bucket. A high-precision stainless steel load cell, hermetically sealed against environmental influences, is used as the sensor element. An integrated temperature sensor compensates for the temperature changes in the weighing mechanism. These sensors have been found to be stable for years. The orifice of the gauge is heated and when snow/ice precipitation occurs, the weight of its water equivalent is the amount observed.
42 ENGINEERING↗
Computational Analysis of Water Film Thickness During Rain Events for Assessing Hydroplaning Risk, Part 1: Nearly Smooth Road Surfaces
In the research work reported here, both two- and three-dimensional computational fluid dynamics (CFD) analysis was used to investigate modern road geometries that were not frequently encountered in the latter half of the 20th century but are much more common today. The relation of newer road geometries to the water film thickness that develops on travel lanes was a major focus of this work.
42 ENGINEERING↗
Constraining microphysical processes of warm rain formulation using advanced spectral separations, an ensemble retrieval framework and machine learning techniques
Drizzle, a common feature of marine boundary layer clouds formed through collision coalescence, plays a key role in cloud microphysics and evolution. Yet, simultaneously retrieving cloud and drizzle properties from remote-sensing observations remains challenging because drizzle droplets often dominate radar signals, masking cloud contributions. The goal of the proposed research is to provide constraints for the process of autoconversion and accretion using ARM cloud measurements. Specifically, we provide concurrent retrievals of cloud and drizzle that allows users to derive corresponding autoconversion and accretion rates.
54 ENVIRONMENTAL SCIENCES↗
Micro Rain Radar / Processed Data
This dataset includes the reflectivity, estimated rainfall rate, liquid water content, and vertical velocity recorded by the MRR2 averaged over 30-second intervals.
17 WIND ENERGY↗
Micro Rain Radar / Raw Data
This dataset includes the reflectivity, estimated rainfall rate, liquid water content, and vertical velocity recorded by the MRR2 averaged over 30 s intervals.
17 WIND ENERGY↗
Radioactive iron rain: transporting {sup 60}Fe in supernova dust to the ocean floor
Several searches have found evidence of {sup 60}Fe deposition, presumably from a near-Earth supernova (SN), with concentrations that vary in different locations on Earth. This paper examines various influences on the path of interstellar dust carrying {sup 60}Fe from an SN through the heliosphere, with the aim of estimating the final global distribution on the ocean floor. We study the influences of magnetic fields, angle of arrival, wind, and ocean cycling of SN material on the concentrations at different locations. We find that the passage of SN material through the mesosphere/lower thermosphere has the greatest influence on the final global distribution, with ocean cycling causing lesser alteration as the SN material sinks to the ocean floor. SN distance estimates in previous works that assumed a uniform distribution are a good approximation. Including the effects on surface distributions, we estimate a distance of 46{sub −6}{sup +10} pc for an 8--10 M{sub ⊙} SN progenitor. This is consistent with an SN occurring within the Tuc-Hor stellar group ∼2.8 Myr ago, with SN material arriving on Earth ∼2.2 Myr ago. We note that the SN dust retains directional information to within 1{sup ◦} through its arrival in the inner solar system, so that SN debris deposition on inert bodies such as the Moon will be anisotropic, and thus could in principle be used to infer directional information. In particular, we predict that existing lunar samples should show measurable {sup 60}Fe differences.
79 ASTRONOMY AND ASTROPHYSICS↗