scholarly journals Observations of Wall Cloud Formation in Supercell Thunderstorms during VORTEX2

2014 ◽  
Vol 142 (12) ◽  
pp. 4823-4838 ◽  
Author(s):  
Nolan T. Atkins ◽  
Eva M. Glidden ◽  
Timothy M. Nicholson
Keyword(s):  
Data Collection ◽  
Conceptual Models ◽  
Flank Region ◽  
The Other ◽  
Cloud Formation ◽  
Cloud Base ◽  
Integrated Analysis ◽  
Low Level ◽  
Rotating Wall ◽  
Supercell Thunderstorms

Abstract This study presents an integrated analysis of dual-Doppler, cloud photogrammetry, surface mobile mesonet, and sounding data to examine wall cloud formation in two supercells observed during the Verification of the Origins of Rotation in Tornadoes Experiment II (VORTEX2). One of the wall clouds contained significant rotation and spawned an (enhanced Fujita) EF2 tornado, while the other was clearly displaced horizontally from the mesocyclone and exhibited little rotation at the time of data collection. Backward parcel trajectories show that the majority of the air entering the wall cloud base originates in the forward-flank region. A small fraction of the parcels enter the wall cloud base from the inflow. Some rear-flank downdraft parcels descend into the strongly rotating wall cloud. For both wall clouds, much of the observed wall cloud lowering is attributed to evaporatively cooled parcels in the forward-flank region being ingested into the low-level updraft. Additional wall cloud-base lowering is observed near the circulation center of the strongly rotating wall cloud. This localized lowering is created by the pressure deficit and associated cooling. The observational results presented herein are compared to long-standing wall cloud formation conceptual models published in the refereed literature.

scholarly journals Breakup of nocturnal low-level stratiform clouds during the southern West African monsoon season

2021 ◽  
Vol 21 (3) ◽  
pp. 2027-2051
Author(s):  
Maurin Zouzoua ◽  
Fabienne Lohou ◽  
Paul Assamoi ◽  
Marie Lothon ◽  
Véronique Yoboue ◽  
...  
Keyword(s):  
West Africa ◽  
Early Morning ◽  
Cloud Formation ◽  
Cloud Base ◽  
Liquid Water Path ◽  
Stratiform Cloud ◽  
Low Level ◽  
Convective Clouds ◽  
Stratiform Clouds ◽  
Lifting Condensation Level

Abstract. Within the framework of the DACCIWA (Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa) project and based on a field experiment conducted in June and July 2016, we analyze the daytime breakup of continental low-level stratiform clouds in southern West Africa. We use the observational data gathered during 22 precipitation-free occurrences at Savè, Benin. Our analysis, which starts from the stratiform cloud formation usually at night, focuses on the role played by the coupling between cloud and surface in the transition towards shallow convective clouds during daytime. It is based on several diagnostics, including the Richardson number and various cloud macrophysical properties. The distance between the cloud base height and lifting condensation level is used as a criterion of coupling. We also make an attempt to estimate the most predominant terms of the liquid water path budget in the early morning. When the nocturnal low-level stratiform cloud forms, it is decoupled from the surface except in one case. In the early morning, the cloud is found coupled with the surface in 9 cases and remains decoupled in the 13 other cases. The coupling, which occurs within the 4 h after cloud formation, is accompanied by cloud base lowering and near-neutral thermal stability in the subcloud layer. Further, at the initial stage of the transition, the stratiform cloud base is slightly cooler, wetter and more homogeneous in coupled cases. The moisture jump at the cloud top is usually found to be lower than 2 g kg−1 and the temperature jump within 1–5 K, which is significantly smaller than typical marine stratocumulus and explained by the monsoon flow environment in which the stratiform cloud develops over West Africa. No significant difference in liquid water path budget terms was found between coupled and decoupled cases. In agreement with previous numerical studies, we found that the stratiform cloud maintenance before sunrise results from the interplay between the predominant radiative cooling, entrainment and large-scale subsidence at its top. Three transition scenarios were observed depending on the state of coupling at the initial stage. In coupled cases, the low-level stratiform cloud remains coupled until its breakup. In five of the decoupled cases, the cloud couples with the surface as the lifting condensation level rises. In the eight remaining cases, the stratiform cloud remains hypothetically decoupled from the surface throughout its life cycle since the height of its base remains separated from the condensation level. In cases of coupling during the transition, the stratiform cloud base lifts with the growing convective boundary layer roughly between 06:30 and 08:00 UTC. The cloud deck breakup, occurring at 11:00 UTC or later, leads to the formation of shallow convective clouds. When the decoupling subsists, shallow cumulus clouds form below the stratiform cloud deck between 06:30 and 09:00 UTC. The breakup time in this scenario has a stronger variability and occurs before 11:00 UTC in most cases. Thus, we argue that the coupling with the surface during daytime hours has a crucial role in the low-level stratiform cloud maintenance and its transition towards shallow convective clouds.

scholarly journals Nocturnal Continental Low-Level Stratus over Tropical West Africa: Observations and Possible Mechanisms Controlling Its Onset

2012 ◽  
Vol 140 (6) ◽  
pp. 1794-1809 ◽  
Author(s):  
Jon M. Schrage ◽  
Andreas H. Fink
Keyword(s):  
West Africa ◽  
Ground Level ◽  
Static Stability ◽  
Cloud Formation ◽  
Cloud Base ◽  
Near Surface ◽  
Low Level ◽  
Stratiform Clouds ◽  
Low Level Jet ◽  
Potential Factors

Abstract Some spatiotemporal characteristics and possible mechanisms controlling the onset of the widespread, low-level nocturnal stratiform clouds that formed during May–October 2006 over southern tropical West Africa are investigated using cloudiness observations from surface weather stations, data from various satellite platforms, and surface-based remote sensing profiles at Nangatchori in central Benin. It is found that the continental stratus is lower than the maritime stratus over the Gulf of Guinea and persists well into the noon hours. For the study period, a clear seasonal cycle was documented, as well as a dependence on latitude with the cloudiest zone north of the coastal zone and south of approximately 9°N. It is also shown that nonprecipitating clear and cloudy nights observed at Nangatchori in central Benin often reflect clearer and cloudier than normal conditions over a wide region of southern West Africa. At Nangatchori, on average the stratus developed at 0236 UTC (about local time) with an extremely low cloud base at 172 m (above ground level) when averaged over all cloudy nights. About 2–3 h before cloudiness onset, a distinct nighttime low-level jet formed that promoted static destabilization and a low Richardson number flow underneath it. The ensuing vertical upward mixing of moisture that accumulated under the near-surface inversion after sunset caused the cloud formation. It is argued that a strong shear underneath the nighttime low-level jet is the major process for cloud formation, but the low-level static stability and the time scale of the shear-driven mixing are other potential factors.

scholarly journals Breakup of nocturnal low-level stratiform clouds during southern West African Monsoon Season

2020 ◽  
Author(s):  
Maurin Zouzoua ◽  
Fabienne Lohou ◽  
Paul Assamoi ◽  
Marie Lothon ◽  
Véronique Yoboue ◽  
...  
Keyword(s):  
Liquid Water ◽  
Early Morning ◽  
Cloud Formation ◽  
Cloud Base ◽  
Liquid Water Path ◽  
Stratiform Cloud ◽  
Low Level ◽  
Convective Clouds ◽  
Initial Stage ◽  
Stratiform Clouds

Abstract. Within the framework of the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud-Interactions over West Africa) project, and based on a field experiment conducted in June and July 2016, we analyse the daytime breakup of the continental low-level stratiform clouds in southern West Africa. We use the observational data gathered during twenty-two precipitation-free occurrences at Savè supersite, in Benin. Our analysis, which starts since the stratiform cloud formation usually at night, focuses on the role played by the coupling between the cloud and the surface in the transition towards shallow convective clouds. It is based on several diagnostics, including Richardson number and various cloud macrophysical properties. The distance between lifting condensation level and cloud base height is used as a criterion of coupling. We also make an attempt to estimate the most predominant terms of the liquid water path budget on early morning. When the nocturnal low-level stratiform cloud forms, it is decoupled from the surface, except in one case. On early morning, the cloud is found coupled with the surface in nine cases and is remained decoupled in the thirteen other cases. The coupling, which occurs within the four hours after the cloud formation, is accompanied with a cloud base lowering and near-neutral thermal stability in the subcloud layer. Further, at the initial stage of the transition, the stratiform cloud base is slightly cooler, wetter and more homogeneous in the coupled cases. The moisture jump at cloud top is found usually around 2 g kg−1, and the temperature jump within 1–5 K, which is significantly smaller than typical marine stratocumulus, and explained by the monsoon flow environment within which the stratiform cloud develops. No significant difference of liquid water path budget terms was found between the coupled and decoupled cases. In agreement with previous numerical studies, we found that the stratiform cloud maintenance before the sunrise results from the interplay between the predominant radiative cooling, and, the entrainment and large scale subsidence at its top. Three transition scenarios were observed, depending on the state of the coupling at the initial stage. In the coupled cases, the low-level stratiform cloud remains coupled until its break up. In five of the decoupled cases, the cloud couples with the surface as the LCL is rising. In the eight remaining cases, the stratiform cloud remains decoupled from the surface all along its life cycle. In case of coupling during the transition, the stratiform cloud base lifts with the growing convective boundary layer roughly between 06:30 and 08:00 UTC. The cloud deck breakup occurring at 11:00 UTC or later leads to the formation of shallow convective clouds. When the decoupling subsists, shallow cumulus clouds form below the stratiform cloud deck between 06:30 and 09:00 UTC. The breakup time in this scenario has a stronger variability, and occurs before 11:00 UTC in most of the cases. Thus we argue that the coupling with the surface during the daytime hours has a crucial role in the low-level stratiform cloud maintenance and in its transition towards shallow convective clouds.

ANALISIS KOHESI DAN KOHORENSI DALAM WACANA BERITA KEMISKINAN DAN RAMADHAN DALAM KORAN REPUBLIKA

2019 ◽  
Vol 1 (01) ◽  
pp. 1-6
Author(s):  
Resdianto Permata Raharjo ◽  
Ahmad Sudali
Keyword(s):  
Qualitative Research ◽  
Data Collection ◽  
The Other ◽  
Coherence Analysis ◽  
Lexical Cohesion ◽  
News Discourse ◽  
The Relationship

This journal explains the results of cohesion and coherence analysis in the current new news discourse in Indonesia published by Republika, Thursday 16 May 2019. The research uses descriptive methods by describing and explaining the results of the analysis found in the study. This research is a type of qualitative research because the results tend to be released and descriptive. the technique used in this study is to take data, data collection is done in two ways, namely listening and taking notes. This study found the results of the use of cohesion and and the use of coherence. Cohesion is the integration between the parts that are characterized by the use of language elements. Cohesion is divided into two parts, lexical cohesion and grammatical cohesion. Grammatical cohesion includes conjunction, reference, release, substitution. Lexical cohesion includes antonyms, synonyms, repetitions, metonymy, and hypomini. Whereas, cohorence is the relationship between elements one with the other elements so that it has an integrated meaning.  

INTERFERENSI GRAMATIKAL DALAM KUMPULAN CERPEN BIARKAN AKU MEMULAI KARYA NURUL F. HUDA

2019 ◽  
Vol 1 (01) ◽  
pp. 16-23
Author(s):  
Zimmatul Liviana
Keyword(s):  
Short Stories ◽  
Data Collection ◽  
Qualitative Method ◽  
Language Variation ◽  
The Other ◽  
Qualitative Descriptive ◽  
Ofthe Object ◽  
Selection Of ◽  
Descriptive Qualitative

The research grammatical interference in a collection ofshort stories Biarkan Aku Memula iwork Nurul F. Hudaisa collection ofshort storiesset in the back that Is start work Let Nurul F. Huda contains many grammatical interference.The problem of this   study were(1)how   the various morphologi calinterference containedin   a   collection of short stories Biarkan Aku Memulai work Nurul F. Huda. (2)how the various syntactic interference contained in a collection of short stories Biarkan Aku Memulai work Nurul F. Huda. The purposeof this studyis to describe the morphological and         Syntactic interference contained in a collection of short stories Biarkan Aku Memulai work Nurul F. Huda. Sociolinguistics is the study of language variation and use in society. Interference is the event of the use of language elements of one into the other language elements that occur in the speakers themselves. This research uses descriptive qualitative method because to describe the actual realityin order to obtainan accurateand objective. Qualitative descriptive methods were used to analyzethe elements ofa word orphrase that incorporated elements of other languages with the analysis and description of the formulation of the problem is the answer. Data collection techniques using observation techniques, the determination ofthe object of research, the selection of short stories.Based on the analysis of the data in this study can be found that there are six forms of interference morphology, namely (1) the prefix nasal N-sound, (2) the addition of the suffix, (3) the exchange prefix, (4) exchange suffixes, (5) exchange konfiks, (6) removal affixes. While the syntactic interference only on the words and phrases in a sentence. The results of the study it can be concluded that the interference morphology more common than syntactic interference.

Integrated Analysis of Low-Level Turbulence around Airport Using Meteorological Model and LES

2013 ◽  
Vol 61 (6) ◽  
pp. 159-166
Author(s):  
Ryota KIKUCHI ◽  
Takashi MISAKA ◽  
Shigeru OBAYASHI ◽  
Tomoo USHIO ◽  
Shigeharu SHIMAMURA ◽  
...  
Keyword(s):  
Integrated Analysis ◽  
Meteorological Model ◽  
Low Level

The Tradition of Religious Books (Kitabs) Printing: Case Study of the Production and Reproduction of Religious Books (Kitabs) in Cianjur and Sukabumi, West Java, Indonesia

2020 ◽  
Vol 17 (2) ◽  
pp. 291-320
Author(s):  
Asep Saefullah
Keyword(s):  
Data Collection ◽  
Screen Printing ◽  
The Other ◽  
West Java ◽  
Simple Method ◽  
Original Essays ◽  
Printed Books ◽  
Religious Books ◽  
Living Tradition

Tulisan ini membahas fenomena penyebaran kitab-kitab cetak keaga­maan di Jawa Barat, khususnya di Sukabumi dan Cianjur. Jenis kitab ini biasanya menggunakan tulisan Arab dengan bahasa Sunda dan menggu­nakan aksara Pegon. Kitab-kitab cetak dari jenis-jenis itu diproduksi dan direproduksi, dan masih digunakan sampai hari ini. Oleh karena itu, fenomena ini dapat disebut sebagai “living tradition”. Pengumpulan data dilakukan dengan melacak dan merekam kitab-kitab yang diproduksi (disalin atau dikarang) dan direproduksi (dicetak atau digandakan) dengan metode seder­hana, yakni fotocopi dan pencetakan tradisional seperti stensil, sablon, dan "cetak toko". Tulisan ini bertujuan untuk memetakan dan merevisi kategorisasi kitab-kitab tersebut dari kajian terdahulu berdasarkan jenis karya, seperti karangan asli, tuqilan, terjemahan, syarḥ (penjelasan), khulasah (ringkasan) yang lain, dan juga berdasarkan bahasa dan aksara yang digunakan. Selain itu, tulisan ini juga mengamati lembaga-lembaga atau individu-individu yang masih mereproduksi buku-buku (kitab-kitab) keagamaan sederhana seperti perusahaan percetakan atau pesantren yang menerbitkan kitab-kitab tersebut. Pada akhir artikel ini, ada beberapa saran dalam upaya untuk melestarikan kitab-kitab cetak dan karya-karya tersebut.Kata kunci: kitab, jenis karya, pencetakan tradisional, Sunda, Pegon, Jawa Barat This paper discusses the phenomenon of the spreading of religious printed books (kitabs) in West Java, especially in Sukabumi and Cianjur, which are characterized by the use of Arabic writing in Sundanese (or known as Pegon script). The printed books (Kitabs) of those types are produced and reproduced, and are still used to this day. Therefore, this phenomenon can be called as a “living tradition”. Data collection was conducted by tracing and recording religious books (kitabs) that are pro-duced (rewritten or compossed) and reproduced (printed or duplicated) with a simple method, known as photocopying and traditional printing such as stencils, screen printing, and “shop printing”. This paper aims to map and revise the categorization of these Kitabs from previous studies based on the types of works including original essays, tuqilan (quotations), translation, sharh (explanation), khulaṣah (summary), or the other, and also based on the language and the script used. In addition, this paper also observes the institutions or individuals that are still reproducing these printed religious books such as the printing company or pesantren that publish such kitabs. At the end of this article, there are some suggestions in attempts to preserve those printed kitabs and the works.Keywords: Kitabs, type of work, traditional printing, Sunda, Pegon, West Java

PENGARUH ABILITY, BENEVOLENCE DAN INTEGRITY TERHADAP TRUST, SERTA IMPLIKASINYA TERHADAP PARTISIPASI PELANGGAN E-COMMERCE: STUDI KASUS PADA PELANGGAN E-COMMERCE DI UBM

2017 ◽  
Vol 2 (2) ◽  
pp. 155-168 ◽  
Author(s):  
David Wong
Keyword(s):  
Data Analysis ◽  
Data Collection ◽  
Structural Equation Model ◽  
Structural Equation ◽  
Likert Scale ◽  
Equation Model ◽  
The Other ◽  
Predictor Variables ◽  
Analysis Method ◽  
Other Hand

This research aims at analyzing (1) the effect of vendor’s ability, benevolence, and integrity variables toward e-commerce customers’ trust in UBM; (2) the effect of vendor’s ability, benevolence, and integrity variables toward the level of e-commerce customers’ participation in Indonesia; and (3) the effect of trust variable toward level of e-commerce customers participation in UBM. This research makes use of UBM e-commerce users as research samples while using Likert scale questionnaire for data collection. Furthermore, the questionnaires are sent to as many as 200 respondents. For data analysis method, Structural Equation Model was used. Out of three predictor variables (ability, benevolence, and integrity), it is only vendor’s integrity that has a positive and significant effect on customers’ trust. On the other hand, it is only vendor’s integrity and customer’s trust that have a positive and significant effect on e-commerce customers’ participation in UBM. Keywords: e-commerce customers’ participation, ability, benevolence, integrity

Coping with longitudinal data in research on developmental psychopathology

2006 ◽  
Vol 30 (1) ◽  
pp. 20-25 ◽  
Author(s):  
David A. Cole
Keyword(s):  
Data Collection ◽  
Longitudinal Data ◽  
Developmental Psychopathology ◽  
Careful Consideration ◽  
Two Dimensions ◽  
The Other ◽  
Outcome Variable ◽  
The Third ◽  
Data Analytic ◽  
Over Time

Many outcome variables in developmental psychopathology research are highly stable over time. In conventional longitudinal data analytic approaches such as multiple regression, controlling for prior levels of the outcome variable often yields little (if any) reliable variance in the dependent variable for putative predictors to explain. Three strategies for coping with this problem are described. One involves focusing on developmental periods of transition, in which the outcome of interest may be less stable. A second is to give careful consideration to the amount of time allowed to elapse between waves of data collection. The third is to consider trait-state-occasion models that partition the outcome variable into two dimensions: one entirely stable and trait-like, the other less stable and subject to occasion-specific fluctuations.

BIOCHEMICAL STUDIES ON SOCKEYE SALMON DURING SPAWNING MIGRATION: IV. THE NON-PROTEIN NITROGENOUS CONSTITUENTS OF THE MUSCLE

1958 ◽  
Vol 36 (8) ◽  
pp. 833-838 ◽  
Author(s):  
J. D. Wood
Keyword(s):  
Sockeye Salmon ◽  
The Other ◽  
Spawning Migration ◽  
Female Fish ◽  
Male And Female ◽  
Low Level ◽  
Early Stages ◽  
Biochemical Studies

The non-protein nitrogenous constituents of muscle of migrating sockeye salmon were investigated. These constituents were found to be the same in both male and female fish and were present in approximately the same amounts in both sexes. The histidine content of the muscle in all fish decreased to one fifth of the original value during the early stages of the migratory journey and remained at the low level thereafter. Some of the other constituents changed to a smaller extent, usually increasing in the later stages of the migration. This was especially noticeable in female fish. However, the increase in the concentration of these constituents in the muscle was due to a decrease in the amount of muscle in the fish rather than to an increase in the amounts of the compounds themselves.

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