Abstract:The equatorial east Indian Ocean is such an important part of the western hemisphere warm pool so that it has great significance for the research of the monsoon system in China and the global climate change.In addition,Indian Ocean is the main part of Maritime Silk Road,thus the surveys in the east Indian Ocean is a reflection of the safety requirements of the Maritime Silk Road.Since 2010,the National Natural Science Foundation of China (NSFC) Indian Ocean Comprehensive Experiment Cruise has been set up for the implementation of the 11th Five-Year Development Plan for NSFC,which greatly promotes interdisciplinary integration in oceanography,enriches the observation data in Indian Ocean,and has made a great number of scientific achievements.This paper introduces the contents,progress and achievements of the comprehensive scientific cruise survey of eastern Indian Ocean oceanography from year 2010 to present,and looks forward to its future.

Abstract:The Madden-Julian Oscillation (MJO) is a dominant component of tropical variability at intraseasonal time scales.The activities of the MJO convection have important impacts on weather and climate systems in many parts of the world.The study of the MJO therefore represents one of the frontiers of atmospheric science.Since the convective initiation is the least understood aspect of MJO,this review aims to synthesize and summarize studies of convective initiation of the MJO include but are not limited to:its observed precursor signals,the numerical simulations,and the mechanisms.The focuses of ongoing research and unsolved issues related to MJO initiation are also presented.

Abstract:Based on the sub-project "Interaction between tropical Indian Ocean circulation dynamics and monsoon and its effect" of the Strategic Priority Research Program of the Chinese Academy of Sciences "Pan-Third Pole environment change study for green Silk Road development",this paper summarizes research progresses on the upper tropical Indian Ocean circulations,the effect of salinity variability on the classical air-sea coupled processes in the Indian Ocean,and the climatic influence of air-sea interaction in the Indian Ocean on the moisture transport over the Pan-Third Pole.Three key scientific issues are then emphasized as follow:three-dimensional linkage mechanism of the upper Indian Ocean circulation variability,response and feedback mechanism of air-sea interactions to the basin-scale thermohaline redistribution in the Indian Ocean,and influence mechanism of Indian Ocean air-sea coupled modes on the climate change over the Pan-Third Pole.Finally,the ultimate objective of this sub-project are also stated,which are:to overall understand the upper ocean circulation systems in the tropical Indian Ocean and advance the understanding of the influence of air-sea interaction in the Indian Ocean on the moisture transport over the Pan-Third Pole;to improve the prediction skill of the Pan-Third Pole climate and promote the security ability of Indian Ocean expedition and channel monitor on the maritime Silk Road;and finally to serve the Belt and Road Initiative.

Abstract:The present study investigates the interdecadal and interannual variations of Sri Lankan precipitation during Southwest Monsoon (SWM) and their connections with the Indian Ocean Sea Surface Temperature (SST) over 38 years (1979-2016).Empirical orthogonal function (EOF) analysis is applied to examine the spatial-temporal variations of precipitation in Sri Lanka and surrounding region.The first two leading EOF modes explain exceeding 70% of the total variance.EOF1 shows a monotonous mode.Both PC1 and 7-yr running mean of precipitation in Sri Lanka show clear interdecadal variations with more and less precipitation before and after 2000.The interdecadal variation of precipitation is associated with the warmer SST in the western and central tropical Indian Ocean during 2000-2014,which induces the anomalous downward motion over Sri Lanka through enhancing the meridional circulation,and thus depresses the precipitation over there.For EOF2 mode,negative signals are in most regions of Sri Lanka except in cape of northern Sri Lanka with positive signals.PC2 shows an interannual variation,and is significantly positively related to the SST anomalies in the southeast Indian Ocean.These warm SST anomalies could induce anomalous cyclonic circulation in the north tropical Indian Ocean due to Gill response,which is favourable for convergences of moisture flux and more precipitation in Sri Lanka.This study suggests that the interdecadal variation of precipitation in Sri Lanka is greatly associated with western and central tropical Indian Ocean SST,while the interannual variation is significantly influenced by the anomalous SST in the southeast tropical Indian Ocean.

Abstract:During summertime,the north Indian Ocean circulation is characterized by eastward Southwest Monsoon Current (SMC) which is essential to the transport of water mass in the west and east ocean basins in the tropics.Occasionally,a narrow westward coastal current (hereafter referred to South Sri Lanka Coastal Current,SSLCC),against Southwest Monsoon (SWM) and SMC,exists off the southern coast of Sri Lanka at the same time.In this study,ECCO data is used to examine the dynamics and inter-annual variations of the narrow westward coastal current.It is found that the formation of the westward SSLCC is closely related to local circulation in the Bay of Bengal (BOB).The southward moving East Sri Lanka Coastal Current (ESLCC) which is associated with the western flank of Sri Lankan Dome (SLD) turns to westward along the northern flank of Small Cyclonic Vortex (SCV).The SCV is a cold upwelling dome,originated at the south of Sri Lanka.The strong SLD is the key factor to intensify the SCV which favors the westward SSLCC.This phenomenon is observed in the years of 1993,2002,2004 and 2011.However,the ESLCC turns to eastward with the SMC during the years which have weaker SLD,such as 1994,1997,2003 and 2008.The possible reason is that the SLD is unable to intensify the SCV.The analysis suggests that the strength of SLD plays a significant role for westward SSLCC.

Abstract:Salinity data from the Ocean Reanalysis System (ORAS4) that implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF),have been used to study the interannual variability of mixed layer salinity in the Arabian Sea mini warm pool (ASMWP) during the period of 1999-2009.Apart from the broad agreement with previous studies on the seasonal salinity observations,we investigated several abnormal interannual high (low) salinity episodes in the mixed layer of the ASMWP.This study concludes the anomalous salinity growth in the mixed layer during July-October in the years of 2003 and 2005 and declining in February-April of 2002 for the study period (1999-2009).Furthermore,the analysis showed that the intensity of the mixed layer salinity and the duration of the ASMWP high salinity period increased when negative Indian Ocean Dipole(nIOD) coincides with the La Nina.Apart from that,the mixed layer salinity budget analysis revealed the dominant role of horizontal advection for the interannual mixed layer salinity changes in the ASMWP.

Abstract:This study mainly focuses on the seasonal and interannual variability of sea surface salinity (SSS) in the Central North Arabian Sea (CNAS) by using Aquarius/Satelite de Aplicaciones Cientificas-D (SAC-D) and the Soil Moisture and Ocean Salinity (SMOS) satellite measurements,and gridded Argo field data from 2011 to 2015.The mean state of spatial SSS variation is consistent among Argo,Aquarius,and SMOS datasets.CNAS has relatively higher SSS with mean of 36.5 practical salinity unit (psu).The lowest SSS in the studied area occurs during February to March and rapidly increases after April.SSS reaches its maximum during the mature phase of southwest summer monsoon period.The CNAS SSS shows significant seasonality due to the advection and evaporation associated with high monsoon winds.As a result of southward advection,high salinity water from the Gulf of Oman and the existence of Ras al Hadd Jet,contribute to the highest SSS during the southwest monsoon period in the CNAS.Northwestward advection of low salinity water from the south,leads to the salinity reduction during northeast monsoon periods in the region.This low SSS advection can reach the Oman Sea during the late winter monsoon period.The inter-annual variability of the CNAS SSS is mainly associated with the monsoonal ocean circulation that triggered by the regional monsoon variation.In particular,it depends on the strength of the northeastern Arabian coastal currents,which transport low salinity water northwestward.

Abstract:Meteorological time-series observations from the Automated Weather Station (AWS) located at 5.936 108°N,80.574 900°E south of Sri Lanka were used to quantify the variability in boundary layer from Dec 2015 to Oct 2016.The observations show the fluctuation of wind,temperature,pressure,relative humidity,precipitation,and downward shortwave radiation,accompanied by monsoon reversing over the northern Indian Ocean during this period of time.The episodic event has been noted by the low air pressure,high relative humidity,high precipitation and reduction of downward radiation during the passage of cyclone Roanu in May 2016.The event is characterized by the rapid increase in temperature,relative humidity,precipitation and wind speed followed by the decline of temperature and precipitation,and the abrupt decrease then dramatic increase in pressure and downward shortwave radiation.The reason behind these fluctuations is investigated using the dataset from AWS during May 2016.The analysis shows that AWS recorded pre-cyclone conditions which start to respond since 13th May,2016.The AWS also recorded post-cyclone conditions which are illustrated by reduction of downward radiation and precipitations after 28th May,2016.These signals are evident for the sustainability of AWS to the cyclone conditions.This study suggests that AWS dataset can be used for weather assessment in southern Sri Lanka region and analysis of air-sea relation phenomena in the southern coastal region.Furthermore,AWS can be used as in situ data source for model validation and parameterization.

Abstract:The Bay of Bengal (BoB) is a high energy active region,dynamics of BoB varies during short term with huge effect over the planktonic environment."Wind pump" induces vertical mixing in the BoB region,which affects the sea surface temperature (SST) and chlorophyll-a (chl-a).This study demonstrates the temporal/seasonal variation of chl-a concentration and its relationship to SST and wind speed.Monthly averaged Aqua-MODIS chl-a data for a period of 10 years (2006-2016) and Sea WiFS monthly climatology data were analyzed.Based on monsoonal chl-a and SST variability,we appraised their relationship and variations over the BoB.Trend analysis of chl-a concentration values shows that vertical mixing is very low in this region with weak annual phase,which reaches its maximum in winter and minimum in summer.About 0.50 mg/m³ is observed during winter as the maximum chl-a concentration value and then decreases since February until summer monsoon period.Summer monsoon period is identified as lack of chl-a concentration,compared to winter monsoon period.In summer monsoon period,especially in July and August,satellite sensors couldn't capture chl-a concentration values accurately due to the dense cloud cover.The R² value for relationship between chl-a concentration and SST is observed to be 0.218 1.

Abstract:A three-dimensional Princeton Ocean Model (POM) along with the observed hourly sea level data are used in this study to investigate the characteristics of the Tide-Surge Interaction (TSI) along the north coast of Sri Lanka in north Indian Ocean.In this study,the cyclone ‘Nisha’ 2008 case was selected and three numerical experiments were performed.The model reproduces reasonably well the tides,surges and total sea water levels and TSI water levels over the study region during this cyclone.The results show that the characteristics of the TSI are significantly shown along the northwestern coast of Sri Lanka.The maximum TSI intensity is associated with the strength and track of the cyclone.In this study,the maximum positive TSI reaches 0.6 m at hour 42 when the TC was strong.At hour 30 when the TC track was relatively weak,the maximum negative TSI reaches about -0.6 m.The magnitude of the interaction current (U_TSI) (0.2 m/s) and the direction of the U_TSI were observed significantly to flow out the northwestern coast.During the whole TC cycle,strong TSI occurs in the northwestern coast of Sri Lanka and the opposite coast of India,which indicates that the tidal effect cannot be ignored in the storm surge simulation in this region.

Abstract:Marlin (Makira sp.) is one of the famous oceanic fish species in Sri Lankan fisheries.To reduce the risk of redistribution of Marlins in the future with the temperature change,it is important to find out the relationship of Marlins with sea surface temperature.Moreover,by identifying this relationship the cost to find the Marlin abundant places in order to catch them can be reduced.In this study,SST values of the year 2006 from Aqua/MODIS images within the region of latitudes 2.0-13.5°N and longitudes 76.5-88.0°E and the simultaneous Marlin catch data obtained from National Aquatic Resources Research & Development Agency were obtained for the analysis.To describe the relationship between SST and Marlins catch per unit effort (CPUE),the Empirical Cumulative Distribution Frequency (ECDF) analysis was used.The temporal variations of SST and fish availability and the relationship between them were analyzed by plotting the data separately for Northeastern,Southeastern,Northwestern and Southwestern areas.Most of the catches could be seen in the western area off the Sri Lankan waters.The fish CPUE changes could be observed with the changes of the SST.Highest frequency of Marlin catches were within the areas with SST of 27-28℃.According to the ECDF analysis,there was a significant relationship between the changes of CPUE and SST values of 22-31℃.The maximum abundance could be seen within 26-31℃.According to the SST changing pattern and the suitable SST values obtained from ECDF analysis,periods of March to May and July to October in Northeastern area,February to June and August to September in Northwestern area,February to July and September to December in Southeastern area,and March to January in Southwestern area are suitable for Marlin fishery.

Abstract:A real-time regional forecasting system for the Eastern Indian Ocean (EIO),called the Experimental Platform of Marine Environment Forecasting for EIO (EPMEF_EIO),is introduced in this paper.EPMEF_EIO consists of a regional atmosphere model and a regional storm surge model,and performs a real-time run four times a day.Output from the Global Forecast System (GFS) from the National Centers for Environmental Prediction (NCEP) is used as the initial and boundary conditions of two nested domains of the atmosphere model,which can exert a constraint on the development of small-and meso-scale atmospheric perturbations through dynamical downscaling.Then the system outputs the 3 day forecast of 72 km,24 km,8 km for Indian Ocean-EIO-Sri Lanka.The forecasted winds at 10 m height from the atmosphere model are used to drive the storm surge model,obtaining the 1/12°-1/36° results for EIO-Sri Lanka.By comparing observation data from the Sri Lanka Station Meteorological Tower of the South China Sea Institute of Oceanology,Chinese Academy of Sciences,TC best track data,and data from the Colombo tide gauge station,it is found that the daily variations of the model forecasted temperature and relative humidity are smaller than the observations;the overall root mean square error (RMSE) of the air temperature is 1.26℃,and the coefficient is 0.8;the overall RMSE of relative humidity is 7.0,and the correlation coefficient is 0.7.The model forecasted wind speed is mostly larger than the observation,with an overall RMSE of 2.3 m/s and a correlation coefficient of 0.65.The forecasted wind direction of the model can grasp the main trend of variation,with an overall RMSE of between 20°-32° and a correlation coefficient of about 0.65.The average error of model track forecast is 110.5 km,166.4 km,and 181.0 km at 24 hour,48 hour,and 72 hour,respectively.In addition,the overall RMSE of the model water level forecast is 0.035 m,accounting for about 5% of the maximum amplitude,and the correlation coefficient with the observation reaches 0.996.This shows that the model has the ability to simultaneously forecast tidal and storm surge processes.EPMEF_EIO,established primarily for research purposes with the potential to be implemented into operations,provides valuable information to the operational forecasters of local marine/meteorological agencies or international TC forecast centers.

Abstract:Many phenomena in the atmosphere and the ocean can be detected by sea surface winds.High quality and high temporal and spatial resolution sea surface wind data product is needed to study these phenomena.In this paper,sea surface winds from Cyclone Global Navigation Satellite System (CYGNSS) mission over 35°N-35°S are validated against in situ observations in order to evaluate the performance of CYGNSS.The in situ wind observations include measurements from the Xisha flux tower in South China Sea (SCS),and moored buoy data from the Global Tropical Moored Buoy Array (GTMBA).The result indicates a mean root-mean-square-difference (RMSD) of 2.17 m/s of CYGNSS winds with respect to in situ observations.Part of this discrepancy may come from instrument error,and part of it may come from representative error because of not-exact match of in situ and satellite measurements.The time evolution of CYGNSS winds,however,is consistent with that of in-situ winds,suggesting its potential application in understanding the complex mass and energy interchange processes of atmosphere and ocean.Examples using surface wind to analyze the MJO and the equatorial eastern Indian Ocean upwelling events are also discussed,which indicates potential applications of CYGNSS observation.

Abstract:Using ERA-interim significant wave height (SWH) and sea surface wind field data from 1979 to 2016,the distribution and changes of extreme wave fields in the South China Sea-north Indian Ocean were analyzed.The results show that the extreme SWH distribution in the South China Sea-North Indian Ocean is highly consistent with extreme wind speed distribution patterns and inter-annual trends,reflecting the fact that extreme SWH is controlled by local extreme wind speeds in the north Indian Ocean and South China Sea.Strong extreme SWH occurs in the Arabian Sea and the northern part of the South China Sea.The growth of the northern Arabian Sea is closely related to the enhancement of cyclone intensity in the region.The extreme SWH in the South China Sea is mainly controlled by the northeast monsoon.The linear SWH growth trend in the east African coast is related to the increasing linear trend in the interdecadal scale of the Somali Jet.The EOF analysis of the extreme SWH anomalies in the north Indian Ocean and the South China Sea showed that the extreme SWH in the South China Sea and the north Indian Ocean showed reversed-phase changes.The extreme SWH in the north Indian Ocean (South China Sea) mostly occurs during the southwest monsoon (northeast monsoon) because extreme wind speeds also relatively increased during that period.

Abstract:Recently there has been more and more focus on the use of social media,like Twitter and Facebook,in disaster prevention and mitigation.China is one of the most serious marine disaster countries in the world,and marine disaster prevention and reduction is an urgent problem to solve.In recent years,the popularization of smart phones and networks has brought Chinese social media into people's daily life.We believe that China's social media has great potential in disaster prevention and mitigation considering the experience of other countries.This paper introduces the use of social media in marine disaster prevention and mitigation in several countries along the 21st Century Marine Silk Road,then summarizes the current situation of China's marine disaster warning,disaster information transmission and disaster management.Finally,some enlightening advices are provided to further improve the application of social media using in China's marine disaster prevention and reduction work by drawing on the successful experience and practice of other countries.