Heavy Cloud Research Articles

Origins of Heavy Precipitation Biases in the TRMM PR and TMI Products Assessed with CloudSat and Reanalysis Data

AbstractThis study aims to characterize the background physical processes in the development of those heavy precipitation clouds that contribute to the Tropical Rainfall Measuring Mission (TRMM) active and passive sensor differences. The combined global observation data from TRMM, CloudSat, and European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) from 2006 to 2014 were utilized to address this issue. Heavy rainfall events were extracted from the top 10% of the rain events from the Precipitation Radar (PR) and TRMM Microwave Imager (TMI) rain-rate climatology. Composite analyses of CloudSat and ERA-Interim were conducted to identify the detailed cloud structures and the background environmental conditions. Over tropical land, TMI tends to preferentially detect deep isolated precipitation clouds for relatively drier and unstable environments, while PR identifies more organized systems. Over the tropical ocean, TMI identifies heavy rainfall events with notable convective organization and clear regional gradients between the western and eastern Pacific Ocean, while PR fails to capture the eastward shallowing of convective systems. The PR–TMI differences for the moist and stable environments are reversed over tropical land.

Numerical Investigation into the effects of obstacles on heavy gas dispersions in the atomsphere

Computational fluid dynamics (CFD) approach is applied to investigate heavy gas dispersion in the atmosphere, under the action of wind. Because of the effect of buoyancy, steady double peaks of the heavy gas concentrations in the downstream area are observed from the numerical results. The double peaks of the concentrations are a special pattern of heavy gas dispersion, which cannot be found in the neutral gas dispersions. Four types of obstacles are placed behind the leakage source to study the influences of these obstacles to the heavy gas dispersions. The numerical results show the detailed shapes and other contents of the heavy clouds under the obstacles.

Validation of SOAR VIIRS Over‐Water Aerosol Retrievals and Context Within the Global Satellite Aerosol Data Record

AbstractThis study validates aerosol properties retrieved using a Satellite Ocean Aerosol Retrieval (SOAR) algorithm applied to Visible Infrared Imaging Radiometer Suite (VIIRS) measurements, from Version 1 of the VIIRS Deep Blue data set. SOAR is the over‐water complement to the over‐land Deep Blue algorithm and has two processing paths: globally, 95% of pixels are processed with the full retrieval algorithm, while the 5% of pixels in shallow or turbid (mostly coastal) waters are processed with a backup algorithm. Aerosol Robotic Network (AERONET) data are used to validate and compare the midvisible (550 nm) aerosol optical depth (AOD), Ångström exponent (AE), and fine mode fraction of AOD at 550 nm (FMF). AOD uncertainty is shown to be approximately ±(0.03 + 10%) for the full and ±(0.03 + 15%) for the backup algorithms, with a small positive median bias around 0.02. When AOD is below about 0.2, the AE and FMF have small negative offsets from AERONET around −0.15 and −0.04, respectively. For higher AOD, AE is less offset and the magnitudes of differences versus AERONET are about ±0.2 and ±0.14, respectively. Aerosol‐type classifications provided by SOAR are found to be reasonable, matching optical‐based classifications from AERONET over 80% of the time. Spatial and temporal patterns of AOD and AE are also compared with those of other contemporary over‐water satellite aerosol data sets; dependent on region, the satellite data sets show varying levels of consistency, with SOAR broadly in‐family, and the largest discrepancies in regions with persistent heavy cloud cover.

CONSIDERATIONS ON THE USE OF SENTINEL-1 DATA IN FLOOD MAPPING IN URBAN AREAS: ANKARA (TURKEY) 2018 FLOODS

Abstract. Flood events frequently occur due to -most probably- climate change on our planet in the recent years. Rapid urbanization also causes imperfections in city planning, such as insufficient considerations of the environmental factors and the lack of proper infrastructure development. Mapping of inundation level following a flood event is thus important in evaluation of flood models and flood hazard and risk analyzes. This task can be harder in urban areas, where the effect of the disaster can be more severe and even cause loss of lives.With the increased temporal and spatial availability of SAR (Synthetic Aperture Radar) data, several flood detection applications appear in the literature although their use in urban areas so far relatively limited. In this study, one flood event occurred in Ankara, Turkey, in May 2018 has been mapped using Sentinel-1 SAR data. The preprocessing of Sentinel-1 data and the mapping procedure have been described in detail and the results have been evaluated and discussed accordingly. The results of this study show that SAR sensors provide fast and accurate data during the flooding using appropriate methods, and due to the nature of the flood events, i.e. heavy cloud coverage, it is currently irreplaceable by optical remote sensing techniques.

Response of phytoplankton to heavy cloud cover and turbidity in the northern Bay of Bengal

An interesting physiological response of phytoplankton to large fluctuations in underwater photosynthetically active radiation (PAR) levels in the northern Bay of Bengal has been presented here. This study is primarily based on a 12-day time series observation in the northern Bay of Bengal during the peak Southwest Monsoon (July 2012), when the study region was recurrently exposed to alternating cloudy and sunny sky conditions. On overcast days, the PAR available underwater at the time series location (TSL) drastically decreased, with the noontime PAR at the surface water (2 m) usually being ~600 µmol m−2 s−1 on sunny days and declining to ~50 µmol m−2 s−1 on heavily overcast days. Closely linked with the sunny and cloudy days at TSL, chlorophyll a concentration in the water column showed noticeable features; it increased in the upper water column (surface-40 m) and decreased in the lower water column (41–80 m) on cloudy days, while the reverse was the case on sunny days. Based on in-situ and laboratory experimental data, it was observed that these temporal changes in the vertical distribution of chlorophyll a in the northern Bay of Bengal were due to the short-term physiological acclimation of phytoplankton to large changes in underwater PAR.

Heavy quark spin multiplet structure of P¯(*)ΣQ(*) molecular states

We study the structure of heavy quark spin (HQS) multiplets for heavy meson-baryon molecular states in a coupled system of $\bar{P}^{(*)}\Sigma_{Q}^{(*)}$, with constructing the one-pion exchange potential with S-wave orbital angular momentum. Using the light cloud spin basis, we find that there are four types of HQS multiplets classified by the structure of heavy quark spin and light cloud spin. The multiplets which have attractive potential are determined by the sign of the coupling constant for the heavy meson-pion interactions. Furthermore, the difference in the structure of light cloud spin gives the restrictions of the decay channel, which implies that the partial decay width has the information for the structure of HQS multiplets. This behavior is more likely to appear in hidden-bottom sector than in hidden-charm sector.

COMPARISON AND ASSESSMENT OF 3D REGISTRATION AND GEOREFERENCING APPROACHES OF POINT CLOUDS IN THE CASE OF EXTERIOR AND INTERIOR HERITAGE BUILDING RECORDING

Abstract. In the field of 3D heritage documentation, point cloud registration is a relatively common issue. With rising needs for Historic Building Information Models (HBIMs), this issue has become more important as it determines the quality of the data to be used for HBIM modelling. Furthermore, in the context of historical buildings, it is often interesting to document both the exterior façades as well as the interior. This paper will discuss two approaches of the registration and georeferencing of building exterior and interior point clouds coming from different sensors, namely the independent georeferencing method and the free-network registration and georeferencing. Building openings (mainly windows) were used to establish common points between the systems. These two methods will be compared in terms of geometrical quality, while technical problems in performing them will also be discussed. Furthermore, an attempt to automate some parts of the workflow using automatic 3D keypoints and features detection and matching will also be described in the paper. Results show that while both approaches give similar results, the independent approach requires less work to perform. However, the free-network method has the advantage of being able to compensate for any systematic georeferencing error on either system. As regards to the automation attempt, the use of 3D keypoints and features may reduce processing time; however correct tie point correspondence filtering remains difficult in the presence of heavy point cloud noise.

Remote Sensing Big Data: Theory, Methods and Applications

Nowadays, our ability to acquire remote sensing data has been improved to an unprecedented level.[...]

Normative or Heavy Clouds? Early Indicators of Nonverbal Learning Disability Based on Mothers’ Reports

Background: Children with Nonverbal Learning Disabilities (NVLD) are verbally competent and particularly weak in nonverbal, visuospatial, and social abilities. Most of the literature about NVLD discusses the all-around functioning and diagnosis process during school years. In this qualitative study, the perceptions of mothers of children with NVLD were explored in the context of their children’s daily functioning characteristics during their first 3 years. The aim was to identify early indicators and warning signs of NVLD during the developmental process.

Cloud structure evolution of heavy rain events from the East-West Pacific Ocean: a combined global observation analysis

Heavy rain events are often associated with flood hazards as one of the most devastating events across the globe. It is therefore essential to identify the evolution of heavy rainfall cloud structures, primarily from global satellite observation, as a tool to provide better disaster early warning systems. To identify the mechanism of heavy rainfall systems and its relationship with cloud development, especially over The Pacific Ocean, we aim to study the westward evolution of the convective systems over this area. Several datasets from Tropical Rainfall Measuring Mission (TRMM), CloudSat GEOPROF product, and ECMWF-reanalysis (ERA) interim were utilized to characterize the evolution. Geolocation and orbital time-lag analysis of the three different datasets for more than 8 years (2006-2014) could provide information related to the evolution of cloud structures associated with heavy rain events. In the first step, a heavy rainfall database was generated from TRMM. The CloudSat coordinate and time position were then matched with TRMM coordinate and time position. All of the processes were programatically conducted in fortran programming language. The result shows a transition between East and West Pacific ocean for TMI data.

Dispersion of carbon dioxide plume in street canyons

Abstract When road tankers or pipelines fail in a city, the released gas generates cloud in street canyons. The toxic heavy gas cloud pollutes the environment and harms the living being’s life. The concentration distribution and trail of the cloud are very important parameters for the emergency response. The wind tunnel experiment and the Computational Fluid Dynamics (CFD) method were applied in studying the transport and dispersion of carbon dioxide (CO2) plume, which was a typical type of heavy gas, in a long street with an intersection. The numerical simulated results using the SST k-ω model were in acceptable agreement with the experimental data. The stationary pre-release flow field in street canyons was characterized by the lee eddy generated on the sharp edges of the building top and sides. In this work, the entire releasing and dispersing process of CO2 can be divided into two stages or two regions. The motion of CO2 cloud was primarily determined by the jet speed and slightly affected by wind in near-source region. The next stage began with the collapse of CO2 cloud. The gravity and wind together influenced the concentration distribution of CO2. Both leakage rate and wind speed had significant impacts on CO2 distribution pattern within an urban street canyon.

Shade tolerance: an additional factor affecting the distribution of mountain beech and silver beech in New Zealand?

Increased shade tolerance and a lower thermal optimum for photosynthesis may give silver beech a photosynthetic advantage over mountain beech in cloudy regions of New Zealand, and possibly the understory. The geographic distributions of silver beech (Lophozonia menziesii) and mountain beech (Fuscospora cliffortioides) in New Zealand roughly correspond with precipitation gradients, with F. cliffortioides dominating in sunny and dry regions, and L. menziesii either dominating or co-dominating with F. cliffortiodes in regions that are more cloudy and moist. Previous research suggests that greater drought tolerance may account for dominance of F. cliffortioides in sunny/dry regions, while greater tolerance of low soil nutrients may render a competitive advantage to L. menziesii in wetter habitats vulnerable to nutrient leaching. In this short communication, we propose and provide preliminary evidence for an additional hypothesis—that greater shade tolerance and a lower thermal optimum for photosynthesis confers a photosynthetic advantage to L. menziesii relative to F. cliffortioides under heavy cloud cover, and possibly in the forest understory. Sunlight measurements were recorded under clear sky, partly cloudy, overcast, and understory conditions at four field sites in New Zealand where the species co-occur, and integrated into previously published photosynthetic light response curves to estimate predicted carbon gain at 10, 20, and 25 °C. Photosynthetic gas exchange measurements were sampled in the field to corroborate expected results. Consistent with our hypothesis, predicted carbon gain was significantly greater in L. menziesii under cool (10–20 °C), low-light ( 20 °C. We conclude that relative tolerance of cloud and canopy shade may be an additional physiological factor, in combination with those previously described in the literature, affecting geographic and ecological distribution of mountain and silver beech in New Zealand.

Passive microwave observations of South America and surrounding oceans from Russian Meteor-M No. 2 and Japan GCOM-W1 satellites

ABSTRACTA new Russian Meteorological Satellite Meteor-M No. 2 with onboard multichannel microwave radiometer MTVZA-GY was launched on sun synchronous orbit in July 2014. The radiometer receives the outgoing radiation of the Earth at 29 channels at the frequency ranges ν = 10–48, 52–57, 90–93 and 176–190 GHz. Conical scanning is performed at the incidence angle 65°. The data derived over the Amazon basin rain forest and the cloudless calm areas in the South Atlantic and South Pacific Ocean and the computed brightness temperatures (TBs) served for the MTVZA-GY external calibration. A comparison of the TB time series obtained by the MTVZA-GY and well-calibrated AMSR2 radiometer onboard GCOM-W1 was used for assessment of the long-term stability of the MTVZA-GY in flight. The joint analysis of the TB time series at ν = 10.6, 42.0 and 91.6 GHz allowed to reveal the variations associated with the wet and dry seasons in the Amazon forest as well as events caused by the rain and heavy clouds during satellite observations. The multichannel approach was also used to study structure, evolution and fields of the sea surface wind, total water vapour content and total cloud liquid water content in the cyclonic formations over the South Atlantic and South Pacific Oceans.

Miasma: a contextual view of air quality with implications for the home environment

ABSTRACTConsumers constantly are negotiating the air in homes. From temperature and comfort to humidity and cleanliness, the air in homes is constantly controlled. Air, air quality, and impacts on health and well-being have been relevant since ancient times. The term miasma refers to a heavy cloud of something unpleasant or unhealthy, and has been used historically to refer to an atmospheric state that caused disease. This paper is a brief overview of miasma as related to the home environment. Using a historical construct, the paper places the intellectual foundations of miasma into a modern context. This manuscript refers to a more modern, figurative connotation. Thus, miasma is interpreted as a destructive entity that surrounds and permeates. This approach provides the academic and student greater understanding of an important housing issue. Given the current emphasis on healthy housing, including indoor air quality, this discussion will broaden the scope of understanding of housing. This note may serve to enhance the dialog about actionable home air quality issues.

Three-dimensional transient numerical model for the thermal performance of the solar receiver

Abstract For solar thermal power plants, no steady-state operation occurs in view of inherently transient natures of their initial and boundary conditions. So this study proposes a mathematical model to perform the analysis on the transient behaviors of the external solar receiver in the tower power technology. This 3D transient model was established by dividing the receiver tube into discrete control volumes and then applying the conservation of thermal energy to every single differential control volume. In addition, this model was validated by simulating the HTF temperature distributions and then comparing them with the reference results. By calculating the time-dependent and non-uniform temperature fields of the receiver tube, this paper focuses attention on the evolution of transient processes in several common scenarios involving the mass flowrate variation, the start-up process and the occurrence of the heavy clouds above the heliostat field. Particularly, the analysis of the transient thermal performance highlights some noteworthy characteristics including serious problems such as the corrosion, the thermal stress and the fatigue in the typical transitions, which might require the control system to correspondingly adjust in time.

Annual Seasonality Extraction Using the Cubic Spline Function and Decadal Trend in Temporal Daytime MODIS LST Data

Examining climate-related satellite data that strongly relate to seasonal phenomena requires appropriate methods for detecting the seasonality to accommodate different temporal resolutions, high signal variability and consecutive missing values in the data series. Detection of satellite-based Land Surface Temperature (LST) seasonality is essential and challenging due to missing data and noise in time series data, particularly in tropical regions with heavy cloud cover and rainy seasons. We used a semi-parametric approach, involving the cubic spline function with the annual periodic boundary condition and weighted least square (WLS) regression, to extract annual LST seasonal pattern without attempting to estimate the missing values. The time series from daytime Aqua eight-day MODIS LST located on Phuket Island, southern Thailand, was selected for seasonal extraction modelling across three different land cover types. The spline-based technique with appropriate number and placement of knots produces an acceptable seasonal pattern of surface temperature time series that reflects the actual local season and weather. Finally, the approach was applied to the morning and afternoon MODIS LST datasets (MOD11A2 and MYD11A2) to demonstrate its application on seasonally-adjusted long-term LST time series. The surface temperature trend in both space and time was examined to reveal the overall 10-year period trend of LST in the study area. The result of decadal trend analysis shows that various Land Use and Land Cover (LULC) types have increasing, but variable surface temperature trends.

Land Surface Phenology and Seasonality Using Cool Earthlight in Croplands of Eastern Africa and the Linkages to Crop Production

Across Eastern Africa, croplands cover 45 million ha. The regional economy is heavily dependent on small holder traditional rain-fed peasant agriculture (up to 90%), which is vulnerable to extreme weather events such as drought and floods that leads to food insecurity. Agricultural production in the region is moisture limited. Weather station data are scarce and access is limited, while optical satellite data are obscured by heavy clouds limiting their value to study cropland dynamics. Here, we characterized cropland dynamics in Eastern Africa for 2003–2015 using precipitation data from Tropical Rainfall Measuring Mission (TRMM) and a passive microwave dataset of land surface variables that blends data from the Advanced Microwave Scanning Radiometer (AMSR) on the Earth Observing System (AMSR-E) from 2002 to 2011 with data from AMSR2 from 2012 to 2015 with a Chinese microwave radiometer to fill the gap. These time series were analyzed in terms of either cumulative precipitable water vapor-days (CVDs) or cumulative actual evapotranspiration-days (CETaDs), rather than as days of the year. Time series of the land surface variables displayed unimodal seasonality at study sites in Ethiopia and South Sudan, in contrast to bimodality at sites in Tanzania. Interannual moisture variability was at its highest at the beginning of the growing season affecting planting times of crops, while it was lowest at the time of peak moisture. Actual evapotranspiration (ETa) from the simple surface energy balance (SSEB) model was sensitive to track both unimodal and bimodal rainfall patterns. ETa as a function of CETaD was better fitted by a quadratic model (r2 > 0.8) than precipitable water vapor was by CVDs (r2 > 0.6). Moisture time to peak (MTP) for the land surface variables showed strong, logical correspondence among variables (r2 > 0.73). Land surface parameters responded to El Niño-Southern Oscillation and the Indian Ocean Dipole forcings. Area under the curve of the diel difference in vegetation optical depth showed correspondence to crop production and yield data collected by local offices, but not to the data reported at the national scale. A long-term seasonal Mann–Kendall rainfall trend showed a significant decrease for Ethiopia, while the decrement was not significant for Tanzania. While there is significant potential for passive microwave data to augment cropland status and food security monitoring efforts in the region, more research is needed before these data can be used in an operational environment.

Running in Place

This article highlights technological performance improvements in the gas turbine industry and its likely future course. While the outlook for commercial aviation gas turbines is bright, the non-aviation segment is decidedly clouded. While analysts have focused on the growing demand for electricity worldwide, the average output of each individual gas turbine unit is also increasing, and at a rate that is faster than that of electricity demand. Gas turbine power plants also have the advantage of dispatchability, which wind, hydroelectric, and solar often do not. A recent econometric study of renewable electric power implementation shows that the use of fast-reacting fossil technologies such as gas turbines to hedge against variability of electrical supply made it more likely to result in the successful investment and use of renewables. The article suggests that gas turbine power plants are cost-effective and can provide a necessary backup to the variability of renewable power plants. Gas turbines combine low cost and fast reaction time in a way that will enable the grid to handle winds dying down unexpectedly or unpredicted heavy clouds diminishing solar power output.

Development of heavy vapour clouds in very low wind speeds

The majority of very large vapour cloud explosions occur in such low wind speeds that vapour flow is gravity-driven. The rate of stripping (or detrainment) of heavy gas by the wind is so low that almost all of the gas released remains in a gas “blanket”, which typically slumps in all directions around the source. Such gravity-driven flammable clouds may extend many hundreds of metres from the source in all directions without significant dilution: their development cannot be assessed with conventional windy dispersion models.Previous work on the basic problem of gravity-driven vapour transport on a flat open surface is reviewed. Existing methods suffer from a number of deficiencies including arbitrary specification of current height and velocity and the neglect of surface friction.A new method of analysis is presented. Close to the source the flow can be calculated from the initial conditions at the source by integration of momentum and continuity equations. Entrainment of fresh air and friction increase the stability of the flow (Richardson number) and the rate of dilution declines towards zero. When the Richardson number approaches unity the current becomes critical and further out from the source the flow is under downstream control.The new method is used to calculate the total dilution of a vapour cloud before entrainment of fresh air is completely suppressed. This determines whether clouds are flammable at long-range. The effects of surface roughness, bund height, vapour density etc. are described.Predictions are compared with data from incidents.

Person-centred phenomenology: service user experiences of exercise

PurposeThe purpose of this paper is to explore the lived experience of sport and exercise amongst a group of mental health service users. Participants were recruited from a north of England NHS mental health trust that was piloting a sport and exercise intervention for adults with mental health needs.Design/methodology/approachIn depth semi-structured interviews were conducted with five mental health service users. The chosen phenomenological methodology was collaborative and interpretive.FindingsTwo essential themes were highlighted: “Intermittent health breaking through heavy clouds of illness” and “The cycle of recovery”. In addition, this person-centred research identified a number of intervention benefits beyond those relating to the impact of physical activity on mental health and wellbeing. The main findings are expressed using visual imagery which participants found expressed their perceptions and experiences better than written prose. This includes the way day-to-day illness impacts on the journey of health for people with mental health problems.Research limitations/implicationsThe intervention looked to help the transition between leaving mental health services and developing a regular routine to promote recovery. The study illuminates the voices of service users and identifies that sport and exercise for mental health service users can be beneficial for recovery and feelings of belonging which can strengthen perceptions of the self.Originality/valueFew studies have approached this methodological approach. This study demonstrates the value of phenomenological research with a collaborative, person-centred or indeed an involved patient focus. This collaborative approach enabled a shared understanding of the phenomena.