scholarly journals CONDITIONS OF MARITIME METEOROLOGY AND OCEANOGRAPHY IN THE VICINITY OF KOTOK ISLAND, SERIBU ISLANDS: APRIL 2011

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Atika Lubis ◽  
Mira Yosi
Keyword(s):  
Coral Reef ◽  
Air Temperature ◽  
Meteorological Data ◽  
Meteorological Parameter ◽  
Surface Wind ◽  
Water Area ◽  
Air Pressure ◽  
Sea Surface ◽  
Monsoon Period ◽  
Oceanographic Parameter

Meteorological data measurement by an Automatic Weather Station (AWS) were carried out at the pier of Kotok Island for East Monsoon period on April 2011 to obtain the changes phenomenon of maritime meteorological parameter and their correlation with the changes of oceanographic condition in shallow waters area and its surrounding. The measurement consists of surface wind parameter, air temperature, humidity, air pressure, and oceanographic data observations such as batimetry, tide, sea current, sea surface temperature, and salinity distributions. Result of maritime meteorological assessment obtained from previous reports (1980, 1998, and 2001) showed that the changes of the maximum air temperature were relatively significant. Furthermore, the air pressure data at the sea surface increased approximately 1.3 mBar. Nevertheless, other meteorological data seemed to be less significant in changes, but indicated a strong correlation with the pattern of tidal current and propagated waves to the shoreline. The changes of oceanographic parameter in the shallow water area were triggered the sedimentation processes, so that the coral reef growth might be decreased.Keywords: Maritime meteorology, oceanographic parameter, flat coral reef

scholarly journals CONDITIONS OF MARITIME METEOROLOGY AND OCEANOGRAPHY IN THE VICINITY OF KOTOK ISLAND, SERIBU ISLANDS: APRIL 2011

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Atika Lubis ◽  
Mira Yosi
Keyword(s):  
Coral Reef ◽  
Air Temperature ◽  
Meteorological Data ◽  
Meteorological Parameter ◽  
Surface Wind ◽  
Water Area ◽  
Air Pressure ◽  
Sea Surface ◽  
Monsoon Period ◽  
Oceanographic Parameter

<p>Meteorological data measurement by an Automatic Weather Station (AWS) were carried out at the pier of Kotok Island for East Monsoon period on April 2011 to obtain the changes phenomenon of maritime meteorological parameter and their correlation with the changes of oceanographic condition in shallow waters area and its surrounding. The measurement consists of surface wind parameter, air temperature, humidity, air pressure, and oceanographic data observations such as batimetry, tide, sea current, sea surface temperature, and salinity distributions. Result of maritime meteorological assessment obtained from previous reports (1980, 1998, and 2001) showed that the changes of the maximum air temperature were relatively significant. Furthermore, the air pressure data at the sea surface increased approximately 1.3 mBar. Nevertheless, other meteorological data seemed to be less significant in changes, but indicated a strong correlation with the pattern of tidal current and propagated waves to the shoreline. The changes of oceanographic parameter in the shallow water area were triggered the sedimentation processes, so that the coral reef growth might be decreased.</p><p>Keywords: Maritime meteorology, oceanographic parameter, flat coral reef</p>

scholarly journals Characteristics and Applications of the Ground-Based X Band Low Elevation Angle Brightness Temperatures under Low Sea State Based on Measured Data

2020 ◽  
Vol 12 (11) ◽  
pp. 1736
Author(s):  
Zhongqing Cao ◽  
Lixin Guo ◽  
Shifeng Kang ◽  
Xianhai Cheng ◽  
Qingliang Li ◽  
...  
Keyword(s):  
Wind Speed ◽  
Meteorological Data ◽  
Surface Wind ◽  
Elevation Angle ◽  
Surface Wind Speed ◽  
Sea Surface ◽  
Sea State ◽  
Sea Surface Wind Speed ◽  
Sea Surface Wind ◽  
X Band

In ground-based microwave radiometer remote sensing, low-elevation-angle (−3°~3°) radiation data are often discarded because they are considered to be of little value and are often difficult to model due to the complicated mechanism. Based on the observed X-band horizontal polarization low elevation angle microwave radiation data and the meteorological data at the same time, this study investigated the generation mechanism of low elevation angle brightness temperature (LEATB) and its relationship with meteorological data, i.e., temperature, humidity, and wind speed, under low sea state. As a result, one could find that the LEATB was sensitive to the atmosphere at the elevation angle between 1° to 3°, and a diurnal variation of the LEATB reached up to 10 K. This study also found a linear relationship between the LEATB and sea surface wind speed under low sea state at an elevation range from −3° to 0°, i.e., the brightness temperature decreased as the wind speed increased, which was inconsistent with the observations at the elevation angle from −10° to −5°. The variation of the LEATB difference according to the change in the over-the-horizon detection capability (OTHDC) of the shipborne microwave radar was examined to identify the reason for this phenomenon theoretically. The results showed that the LEATB difference was significantly influenced by a change in the OTHDC. Further, this study examined a remote sensing method to extract the sea surface wind speed data from experimental LEATB data under low sea state. The results demonstrated that the X-band horizontal polarization LEATBs were useful to retrieve the sea surface wind speed data at a reasonable accuracy—the root mean square error of 0.02408 m/s. Overall, this study proved the promising potential of the LEATB data for retrieving temperature profiles, humidity profiles, sea surface winds, and the OTHDC.

scholarly journals Latent Heat Flux Sensitivity to Sea Surface Temperature: Regional Perspectives

2017 ◽  
Vol 30 (1) ◽  
pp. 129-143 ◽  
Author(s):  
B. Praveen Kumar ◽  
Meghan F. Cronin ◽  
Sudheer Joseph ◽  
M. Ravichandran ◽  
N. Sureshkumar
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Global Analysis ◽  
Surface Wind ◽  
Sea Surface ◽  
State Variables ◽  
Monsoon Period

A global analysis of latent heat flux (LHF) sensitivity to sea surface temperature (SST) is performed, with focus on the tropics and the north Indian Ocean (NIO). Sensitivity of LHF state variables (surface wind speed Ws and vertical humidity gradients Δq) to SST give rise to mutually interacting dynamical (Ws driven) and thermodynamical (Δq driven) coupled feedbacks. Generally, LHF sensitivity to SST is pronounced over tropics where SST increase causes Ws (Δq) changes, resulting in a maximum decrease (increase) of LHF by ~15 W m−2 (°C)−1. But the Bay of Bengal (BoB) and north Arabian Sea (NAS) remain an exception that is opposite to the global feedback relationship. This uniqueness is attributed to strong seasonality in monsoon Ws and Δq variations, which brings in warm (cold) continental air mass into the BoB and NAS during summer (winter), producing a large seasonal cycle in air–sea temperature difference ΔT (and hence in Δq). In other tropical oceans, surface air is mostly of marine origin and blows from colder to warmer waters, resulting in a constant ΔT ~ 1°C throughout the year, and hence a constant Δq. Thus, unlike other basins, when the BoB and NAS are warming, air temperature warms faster than SST. The resultant decrease in ΔT and Δq contributes to decrease the LHF with increased SST, contrary to other basins. This analysis suggests that, in the NIO, LHF variability is largely controlled by thermodynamic processes, which peak during the monsoon period. These observed LHF sensitivities are then used to speculate how the surface energetics and coupled feedbacks may change in a warmer world.

scholarly journals ANALISIS HUJAN ES DI KOTA LUBUKLINGGAU DENGAN MEMANFAATKAN DATA CITRA SATELIT HIMAWARI-8 DAN RADIOSONDE

2019 ◽  
Vol 3 ◽  
pp. 130
Author(s):  
Heriyanto Wicaksono ◽  
Fazrul Rafsanjani Sadarang ◽  
Ahmad Fadlan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Imagery ◽  
Air Temperature ◽  
Air Pressure ◽  
Peak Temperature ◽  
Sea Surface ◽  
Atmospheric Conditions ◽  
Air Humidity ◽  
Sumatra Island

<p class="AbstractEnglish"><strong>Abstract:</strong> The phenomenon of hail again hit Indonesia. The hail occurred in Lubuklinggau City, South Sumatra on October 15 2018, at around 16.20 WIB. Based on AWS Tugu Mulyo observation data, the rainfall on 15 October 2018 was recorded at 26.8 mm which included the medium rainfall category according to BMKG. This research aims to analyze the state of the atmosphere, satellite imagery, sea surface temperature anomalies, and air lability during the hailstorm in Lubuklinggau. Analysis of atmospheric conditions using air temperature data (T), air humidity (RH), and air pressure (P) results of observations of the surface before, during, and after the event. The Himawari satellite image with a resolution of 0.02º x 0.02º is processed with the SATAID application and is used to view the cloud growth phase. Air lability was analyzed by processing radiosonde data from Weather Wyoming Web using the RAOB application 5.7. The results of the analysis show that in the event of hail, the surface air temperature has decreased significantly, the surface air humidity has a significant increase, and the lowest surface air pressure is lower than the day before the hail. The air lability index shows that before the occurrence of hail, atmospheric conditions are unstable causing massive growth of convective clouds. The anomaly of sea surface temperature around Sumatra Island is quite warm, which is 0.5ºC. 1,8ºC which results in the possibility of cloud formation around Sumatra Island getting bigger. Based on satellite imagery, the peak temperature of the cloud at 16.00 WIB is -10.3ºC and at 16.10 WIB the cloud peak temperature reaches -67.8ºC. The significant decrease in cloud peak temperature in the 10-minute period indicates the presence of cloud growth due to a very strong updraft so that the peak temperature of the cloud becomes very cold. The temperature of the cloud peak reaching -67.8ºC shows that there is a convective cloud that is strong enough when there is hail in Lubuklinggau.</p><p class="KeywordsEngish"><strong>Abstrak:</strong> Fenomena hujan es kembali melanda Indonesia. Hujan es tersebut terjadi di Kota Lubuklinggau, Sumatra Selatan pada tanggal 15 Oktober 2018 sekitar pukul 16.20 WIB. Berdasarkan data pengamatan AWS Tugu Mulyo, curah hujan pada tanggal 15 Oktober 2018 tercatat sebesar 26,8 mm yang termasuk kategori hujan sedang menurut BMKG. Penelitian kali ini bertujuan untuk menganalisis keadaan atmosfer, citra satelit, anomali suhu permukaan laut, dan labilitas udara pada saat terjadi hujan es di Lubuklinggau<em>. </em>Analisis keadaan atmosfer menggunakan data suhu udara (T), kelembapan udara (RH), dan tekanan udara (P) hasil pengamatan permukaan sebelum, saat, dan sesudah kejadian. Citra satelit Himawari dengan resolusi 0.02º x 0.02º diolah dengan aplikasi SATAID dan digunakan untuk melihat fase pertumbuhan awan. Labilitas udara dianalisis dengan mengolah data radiosonde dari <em>Weather Wyoming Web</em> menggunakan aplikasi RAOB 5.7. Hasil analisis menunjukkan bahwa pada saat terjadi hujan es, suhu udara permukaan mengalami penurunan yang signifikan, kelembapan udara permukaan mengalami kenaikan yang signifikan, serta tekanan udara permukaan terendah lebih rendah daripada hari sebelum terjadinya hujan es. Indeks labilitas udara menunjukkan bahwa sebelum terjadinya hujan es, kondisi atmosfer dalam keadaan labil sehingga menyebabkan pertumbuhan awan konvektif yang masif. Anomali suhu permukaan laut di sekitar Pulau Sumatera cukup hangat, yaitu 0,5ºC s.d. 1,8ºC yang mengakibatkan peluang terbentuknya awan di sekitar Pulau Sumatera semakin besar. Berdasarkan citra satelit, suhu puncak awan pada jam 16.00 WIB sebesar -10,3ºC dan pada jam 16.10 WIB suhu puncak awan mencapai -67,8ºC. Penurunan suhu puncak awan yang signifikan dalam kurun waktu 10 menit tersebut mengindikasikan adanya pertumbuhan awan akibat <em>updraft </em>yang sangat kuat sehingga suhu puncak awan menjadi sangat dingin. Suhu puncak awan yang mencapai -67,8ºC menunjukkan bahwa terdapat awan konvektif yang cukup kuat saat teradi hujan es di Lubuklinggau.</p>

Summer Nonconvective Severe Wind Frequency over Ontario and Its Correlation with Tropical Pacific Sea Surface Temperature

2014 ◽  
Vol 53 (5) ◽  
pp. 1170-1182 ◽  
Author(s):  
Da-Lin Zhang ◽  
Zuohao Cao ◽  
Jianmin Ma ◽  
Aiming Wu
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Regional Climate ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
Kendall Test ◽  
Tropical Pacific ◽  
Sea Surface ◽  
Positive Trend ◽  
Climate Conditions

AbstractThe summer nonconvective severe surface wind (NCSSW) frequency over Ontario, Canada, in relation to regional climate conditions and tropical Pacific Ocean sea surface temperatures (SSTs) during the period of 1979–2006 is examined using surface wind reports and large-scale analysis data. A statistically robust positive trend in Ontario summer NCSSW frequency is identified using three independent statistical approaches, which include the conventional linear regression that has little disturbance to the original time series, the Mann–Kendall test without a lag-1 autoregressive process, and the Monte Carlo simulation. A composite analysis of the large-scale monthly mean data reveals that the high- (low-) NCSSW occurrence years are linked to stronger (weaker) large-scale horizontal pressure gradients and more (less) intensive vector wind anomalies in the upper troposphere. Unlike the low-event years, anomalous anticyclonic circulations are found at 500 and 250 hPa in the high-event years, which are conducive to downward momentum transport and favorable for severe surface wind development. It is also found that the summer NCSSW occurs more frequently under the conditions of warmer surface air temperature over Ontario. Further analyses indicate that an increase in the summer NCSSW frequency is well correlated with an increase in the previous winter SSTs over the eastern equatorial Pacific, namely, in the Niño-1+2 and Niño-3 areas, through a decrease in sea level pressure over northern Ontario and an increase in surface air temperature over central and southern Ontario.

scholarly journals HF RADAR MAPPING OF EXTENSIVE OCEAN WINDFIELDS

1980 ◽  
Vol 1 (17) ◽  
pp. 20 ◽  
Author(s):  
P.E. Dexter ◽  
R.C. Casey
Keyword(s):  
Meteorological Data ◽  
Wave Spectrum ◽  
Surface Wind ◽  
Doppler Frequency ◽  
Hf Radar ◽  
Sea Surface ◽  
Propagation Mode ◽  
Wave Spectra ◽  
Radio Waves ◽  
Sea Wave

The possibility of deriving parameters of sea wave spectra remotely from characteristics of radio waves at high frequency (HF) scattered from the sea surface was first raised when Crombie (1955) correctly deduced that Doppler frequency shifts in the signal returned from short range in his HF radar resulted uniquely from components of the sea wave spectrum having wavelengths exactly one-half the radio wavelength, and travelling radially with respect to the radar. Since then the technique has been expanded in two directions: (a) The use of ionospherically propagated-JiF radio waves ('Skywave' HF radar) to^ examine extensive ocean areas out to some 4000 km from the observing site, to obtain oceanographic and meteorological data suitable for input to synoptic observation systems. This approach has been developed through the experimental work of Tveten (1967) and Ward (1969), and the empirical technique proposed by Long and Trizna (1973) to allow the simple extraction of sea surface wind vectors from Doppler spectra of the backscattered radio signals. (b) The determination of directional sea wave spectra and sea surface currents at short ranges with HF radars operating in the groundwave propagation mode, based on theoretical analyses of the scattering process such as those of Barrick (1972). The HF Skywave radar constructed and operated at Townsville by the Physics Department of James Cook University has been employed for some years now on research into the possibilities for mapping sea states and sea surface winds over ocean areas surrounding Australia (Ward, 1969; Ward and Dexter, 1976; Dexter and Casey, 1978).

SATELLITE DATA FOR INVESTIGATION OF RECENT STATE AND PROCESSES IN THE SIVASH BAY

2017 ◽  
Author(s):  
Ekaterina Shchurova ◽  
Ekaterina Shchurova ◽  
Rimma Stanichnaya ◽  
Rimma Stanichnaya ◽  
Sergey Stanichny ◽  
...  
Keyword(s):  
Satellite Data ◽  
Water Exchange ◽  
High Salinity ◽  
Meteorological Data ◽  
Sea Surface ◽  
Azov Sea ◽  
Seasonal Wind ◽  
Ice Regime ◽  
Very High

Sivash bay is the shallow-water lagoon of the Azov Sea. Restricted water exchange and high evaporation form Sivash as the basin with very high salinity. This factor leads to different from the Azov Sea thermal and ice regimes of Sivash. Maine aim of the study presented to investigate recent state and changes of the characteristics and processes in the basin using satellite data. Landsat scanners TM, ETM+, OLI, TIRS together with MODIS and AVHRR were used. Additionally NOMADS NOAA and MERRA meteorological data were analyzed. The next topics are discussed in the work: 1. Changes of the sea surface temperature, ice regime and relation with salinity. 2. Coastal line transformation – long term and seasonal, wind impact. 3. Manifestation of the Azov waters intrusions through the Arabat spit, preferable wind conditions.

scholarly journals Utilising Open Geospatial Data to Refine Weather Variables for Building Energy Performance Evaluation—Incident Solar Radiation and Wind-Driven Infiltration Modelling

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 802
Author(s):  
Kristian Skeie ◽  
Arild Gustavsen
Keyword(s):  
Solar Radiation ◽  
Web Service ◽  
Meteorological Data ◽  
Surface Wind ◽  
Building Energy ◽  
Energy Performance ◽  
Geospatial Data ◽  
Weather Data ◽  
Building Site ◽  
Incident Solar Radiation

In building thermal energy characterisation, the relevance of proper modelling of the effects caused by solar radiation, temperature and wind is seen as a critical factor. Open geospatial datasets are growing in diversity, easing access to meteorological data and other relevant information that can be used for building energy modelling. However, the application of geospatial techniques combining multiple open datasets is not yet common in the often scripted workflows of data-driven building thermal performance characterisation. We present a method for processing time-series from climate reanalysis and satellite-derived solar irradiance services, by implementing land-use, and elevation raster maps served in an elevation profile web-service. The article describes a methodology to: (1) adapt gridded weather data to four case-building sites in Europe; (2) calculate the incident solar radiation on the building facades; (3) estimate wind and temperature-dependent infiltration using a single-zone infiltration model and (4) including separating and evaluating the sheltering effect of buildings and trees in the vicinity, based on building footprints. Calculations of solar radiation, surface wind and air infiltration potential are done using validated models published in the scientific literature. We found that using scripting tools to automate geoprocessing tasks is widespread, and implementing such techniques in conjunction with an elevation profile web service made it possible to utilise information from open geospatial data surrounding a building site effectively. We expect that the modelling approach could be further improved, including diffuse-shading methods and evaluating other wind shelter methods for urban settings.

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