Vol 3 , No 2 (In publishing)





Table of Contents

Articles

by Kazuyoshi Suzuki 1, Milija Zupanski 2
203 Views, 162 PDF Downloads

Regions of the cryosphere, including the poles, that are currently unmonitored are expanding, therefore increasing the importance of satellite observations for such regions. With the increasing availability of satellite data in recent years, data assimilation research that combines forecasting models with observational data has begun to flourish. Coupled land/ice-atmosphere/ocean models generally improve the forecasting ability of models. Data assimilation plays an important role in such coupled models, by providing initial conditions and/or empirical parameter estimation. Coupled data assimilation can generally be divided into three types: uncoupled, weakly coupled, or strongly coupled. This review provides an overview of coupled data assimilation, introduces examples of its use in research on sea ice-ocean interactions and the land, and discusses its future outlook. Assimilation of coupled data constitutes an effective method for monitoring cold regions for which observational data are scarce and should prove useful for climate change research and the design of efficient monitoring networks in the future.

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Articles

by A. Narendra Babu 1, V. Naveen Kumar 2, P. S. Brahmanandam 3, M. Purnachandra Rao 4, M. Roja Raman 5, K. Sreedhar 6
49 Views, 45 PDF Downloads

This research reports, for the first time, an anomalous wind circulation over Taipei (Latitude 25.030N, Longitude 121.510E), Taiwan during the northern hemisphere winter season (December, January, and February) of years 2004 and 2005. The anomalous wind circulation of meridional winds, which showed southward directions during the winter seasons of 2004 and 2005 instead of northward winds, is noticed from one kilometer altitude range (lower troposphere) and that trend continued till around 20 km altitude range (lower stratosphere). To ascertain whether such a disturbed nature of wind pattern existed over nearby locations to Taipei, we have analyzed radiosonde-measured meridional and zonal winds over four nearby stations station to Taipei including, Roig, Xiamen, Minami and Fuzhou. Surprisingly, no anomalous wind behavior is seen except over Taipei during the northern winter seasons of 2004 and 2005. On the other hand, the European Centre for Medium-Range Weather Forecasts (ECMWF) model-predicted winds do not show any anomalous wind patterns over Taipei and other nearby stations, possibly due to the large averaging of internal variabilities of reanalysis databases. The plausible physical mechanisms of these disturbed meridional wind patterns are not understood at this juncture, but it is believed that local winds and atmospheric pollutants might have created an amicable environment as to provide such a disturbed meridional wind pattern over Taipei, Taiwan in the winter season of 2004 and 2005.

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Articles

by Annie Melinda Paz-Alberto 1, Edmark P. Bulaong 1, Ranilo B. Lao 1, Eleazar V. Raneses 1, Bennidict P. Pueyo 1
58 Views, 36 PDF Downloads
Geophysical changes of the river outlets, riverbanks and coastlines in Alaminos, Pangasinan were measured using Google Earth from 2009 to 2014. On the other hand, actual measurements were gathered using South Total Station (NTS-362R6L) in 2015. The insights of the residents regarding feature changes of the river were obtained through one on one interview. Root Mean Square Errors (RMSE) were computed for measurement and horizontal positional accuracy of Google Earth. To perceive the effects of sea levels, historical data (2004-2015) from Bolinao, Philippines Tide Chart at online tides and currents predictions were also analyzed. Alaminos river outlets decreased in width size due to natural factor and human activities. Alaminos riverbank increased in width size which could be possibly due to natural calamities and weak bank resistance brought about by the frequent flooding caused by heavy rains and the emergency released of water from San Roque Dam. Generally the north and south coasts of Alaminos River increased and expanded. Rise in sea level is also a probable cause of changes wherein heights of low tides in Pangasinan Gulf is increasing overtime. The computed RMSE was low which indicate positional accuracy and measurement of Google Earth in the study area.
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Articles

by Jhuma Biswas 1
55 Views, 50 PDF Downloads
This study examines the long term trend of the radiatively active atmospheric aerosols which can influence the Earth’s energy budget directly by scattering and absorbing radiation and indirectly by acting as cloud condensation nuclei. MODIS sensor on board the NASA Earth Observing System Terra and Aqua satellite based Aerosol Optical Depth (AOD) data are used for long term analysis of aerosols over Bongaigaon, Assam for the period August, 2002 to March, 2017. Highest AOD values are observed in pre-monsoon (March-May) season due to long range transportation as well as intense biomass burning activities especially as a part of Jhum cultivation. In general, AOD values are low in post-monsoon (October-November) season which may be due to wash out of aerosols by rain in the preceding months without enough replacement. The monthly AOD values vary from its highest value 0.949 in April, 2016 to its lowest value 0.107 in November, 2002 for the study period. From the comparison of MODIS Terra and Aqua AOD at 550 nm, it is clearly seen that generally Terra AOD at 10:30 hr is higher than the Aqua AOD at 13:30hr. A slowly increasing trend of both Aqua and Terra AOD at 550 nm is observed over the study location. The observed Ångström exponent value varies from its minimum value in monsoon season to its maximum value in winter season. With increasing AOD values, horizontal visibility decreases over Bongaigaon.
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Articles

by Bilal Hammoud 1,2, Fabien Ndagijimana 2, Ghaleb Faour 3, Hussam Ayad 1, Majida Fadlallah 1, Jalal Jomaah 1
38 Views, 42 PDF Downloads
Oil spill in sea water is one of the main accidents that affect significantly the maritime environment over a long period of time. Knowing the severe influence of oil spills on the ecosystem, it is crucial to have oil spill detecting and monitoring systems for quick intervention and danger containment. In our project, we propose the usage of drones as an oil spill detection system. The drones will be implementing different previously developed multi-frequency approaches for the detection. The effectiveness of such techniques is based on the accuracy of the data collected and their match to the theory. This journal presents a method for the remote extraction of reflection coefficients from multilayer structure modeling an oil spill in sea water. The experimental results for the reflectivity extraction validate the theoretical calculations and allow the implementation of different algorithms based on the statistical information taken directly from the site.
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Articles

by Fanghua Xu 1
62 Views, 16 PDF Downloads

A simple temperature-dependent wind stress scheme is implemented in National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM), aiming to enhance positive wind stress and sea surface temperature (SST) correlation in SST-frontal regions. A series of three-year coupled experiments are conducted to determine a proper coupling coefficient for the scheme based on the agreement of surface wind stress and SST at oceanic mesoscale between model simulations and observations. Afterwards, 80-year simulations with/without the scheme are conducted to explore its effects on simulated ocean states and variability.
The results show that the new scheme indeed improves the positive correlation between SST and wind stress magnitude near the large oceanic fronts. With more realistic surface heat flux and wind stress, the global SST biases are reduced. The global ocean circulation represented by barotropic stream function exhibits a weakened gyre circulation close to the western boundary separation, in agreement with previous studies. The simulation of equatorial Pacific current system is improved as well. The overestimated El Niño Southern Oscillation (ENSO) magnitude in original CESM is reduced by ~30% after using the new scheme with an improved period.

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Articles

by Kenza KHOMSI 1,2, Houda NAJMI 2, Zineb SOUHAILI 1
51 Views, 6 PDF Downloads
Temperature is the first meteorological factor to be directly involved in leading ozone (O3) extreme events. Generally, upward temperatures increase the probability of having exceedance in ozone adopted thresholds. In the global climate change context more frequent and/or persistent heat waves and extreme ozone (O3) episodes are likely to occur during in coming decades and a key question is about the coincidence and co-occurrence of these extremes. In this paper, using 7 years of surface temperature and air quality observations over two cities from Morocco (Casablanca and Marrakech) and implementing a percentile thresholding approach, we show that the extremes in temperature and ozone (O3) cluster together in many cases and that the outbreak of ozone events generally match the first or second days of heat waves. This co-occurrence of extreme episodes is highly impacted by humidity and may be overlapping large-scale episodes.
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Articles

by Jianli Li 1, Yun Wang 1, Pengfei Dang 1, Zhaoxing Lu 1,2
50 Views, 7 PDF Downloads
The attitude determination method plays an important role in SINS/CNS integrated system for spacecraft. Since the misalignment angels are indirect measurements, the misalignment angle model used in the existing attitude determination method can cause transformation errors. To solve the problem, an attitude determination method based on convected Euler angle error model for SINS/CNS integrated system is proposed. The attitude error propagation is analyzed, and the convected Euler angle error model is derived. Furthermore, the state equation of SINS/CNS integrated system is established. The Kalman filter estimates and compensates the Euler angle errors. Finally, simulation results verified that the proposed method can improve the attitude accuracy compared to the conventional misalignment angle method.
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Articles

by Annie Melinda Paz-Alberto 1, Edmark P. Bulaong 1, Jose T. Gavino 1, Christopher R. Genaro 1, Ranilo B. Lao 1
47 Views, 12 PDF Downloads
Remote sensing offers fast, cheap and reliable method in detecting river and coastal changes. In this study, satellite imageries of Morong river and coastlines from 2006 to 2016 were collected and analyzed to monitor changes. Field measurements were also done using South Total Station (NTS-362R6L) in 2016 for comparison and validation of data. Results showed that the river outlet and the riverbank increased in width size due to erosion brought about by torrential rains and urban run-offs. Coastlines near the river narrowed in size or shifted landward due to coastal erosion and sea level rise. An interview was conducted to locals residing nearby the river and coast where strong typhoons were reported which cause geophysical changes in the area. The residents also observed sea level rise, coastal and river erosion which caused narrowing of the coastlines and widening of the river, respectively. Records of high tides and low tides collected were projected in annual average levels per month. The average level of low tides increased per year which can be a result of sea level rise. The computed RMSE between field and remote sensing measurements ranged from 0.1m to 0.67m which indicated positional accuracy of Google Earth in the area.
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