Ocean Remote Sensing Research Articles

Efficient Retrieval of Massive Ocean Remote Sensing Images via a Cloud-Based Mean-Shift Algorithm.

The rapid development of remote sensing (RS) technology has resulted in the proliferation of high-resolution images. There are challenges involved in not only storing large volumes of RS images but also in rapidly retrieving the images for ocean disaster analysis such as for storm surges and typhoon warnings. In this paper, we present an efficient retrieval of massive ocean RS images via a Cloud-based mean-shift algorithm. Distributed construction method via the pyramid model is proposed based on the maximum hierarchical layer algorithm and used to realize efficient storage structure of RS images on the Cloud platform. We achieve high-performance processing of massive RS images in the Hadoop system. Based on the pyramid Hadoop distributed file system (HDFS) storage method, an improved mean-shift algorithm for RS image retrieval is presented by fusion with the canopy algorithm via Hadoop MapReduce programming. The results show that the new method can achieve better performance for data storage than HDFS alone and WebGIS-based HDFS. Speedup and scaleup are very close to linear changes with an increase of RS images, which proves that image retrieval using our method is efficient.

Foreword to the Special Issue on the Remote Sensing of the World Oceans

The papers in this special issue are devoted to the deployment of remote sensing for ocean research. The contents are organized in six areas: Ocean applications with SAR remote sensing; Meso-scale and large-scale oceanic variability studies using altimeter data; Ocean surface and bathymetry feature detections with high-resolution true-color imagery; Ocean color remote sensing; Instrument calibration and validation; and Ocean surface wind retrieval with new instruments.

Ocean remote sensing for sustainable resources

This is a special issue featuring a selection of research papers presented at the 12th Biennial Pan Ocean Remote Sensing Conference (PORSEC) in November 2014. Since its establishment in 1990 as the...

Ocean Salinity and the Aquarius/SAC-D Mission: A New Frontier in Ocean Remote Sensing

Ocean Salinity and the Aquarius/SAC-D Mission: A New Frontier in Ocean Remote Sensing

2013 Microwave Ocean Remote Sensing Training School

2013 Microwave Ocean Remote Sensing Training School

Introduction to the Special Issue on Ocean Remote Sensing With Synthetic Aperture Radar

Introduction to the Special Issue on Ocean Remote Sensing With Synthetic Aperture Radar

2013 Microwave Ocean Remote Sensing Training School

2013 Microwave Ocean Remote Sensing Training School

Connecting regional impacts to global environmental change

This is a special issue that features a selection of research articles presented at the Tenth Biennial Pan Ocean Remote Sensing Conference (PORSEC) in October 2010. Primarily through volunteer effo...

Prakiraan Kesuburan Perairan Bali Dari Citra Satelit <br><i>[Forecast Fertility Bali Waters From Satellite Imagery]<i>

Abstract Aplication Ocean Remote Sensing technology to many use for field fisheries, once use this technology in forecast fertility water. The aim of this study was to determine the feasibility of Bali coastal area for cage of pearl oyster culture. The method used is a descriptive method of data collection. Satellite image processing activities Aqua/Terra Modis starting with the collection of satellite image data from the database NASA via OceanColor Web site, the selection of a clean image data, and than download of satellite images. The first stages of image data processing are used software ENVI 4.7, with procedures are coloring the image, limiting the minimum and maximum temperatures and sea surface chlorophyll-a, and classifiying of the image based on the value of sea surface temperature. Sea surface temperature parameter determine the location of the cage of pearl oysters (Pinctada maxima) culture. Suitability of the location of the cage of pearl oyster culture on Bali coastal area, at coordinates 8° 33' 00.97 " - 8° 42' 05.30" South Latitude and 115° 18' 03.40 " - 115° 39 ' 03.21" East Longitude. Based on geographical, that the location in the southeastern Bali coastal area and on the northern area of Nusa Pennida island.

A comparative assessment of IRS-P4 (MSMR)-derived sea surface temperature and sea surface wind speed over the north Indian Ocean

Indian Remote Sensing Satellite (IRS-P4) multi-frequency scanning microwave radiometer (MSMR) provides geophysical parameters like sea surface temperature (SST), sea surface wind speed (SSWS), integrated water vapour (IWV) and cloud liquid water (CLW). The retrieval procedure of these parameters given by Gohil et al. (2000, Geophysical parameter retrieval over global oceans from IRS-P4 (MSMR). In Preprints, Fifth Pacific Ocean Remote Sensing Conference, 5–8 December 2000, Goa, India (Goa: National Institute of Oceanography), pp. 207–211) was summarized by Sharma et al. (2002, Identification of large scale atmospheric and oceanic features from IRS-P4 multifrequency scanning microwave radiometer: preliminary results. Journal of Atmospheric and Oceanic Technology, 19, pp. 1127–1134) and Jena (2007, Studies on the retrieval, validation and applications of geophysical parameters from IRS-P4 (MSMR) data. PhD thesis, Berhampur University, Orissa). Demonstration of self-consistency of these parameters has primary scientific importance. This article deals with the validation of MSMR geophysical parameters such as SST and SSWS with in situ observations (buoy data) over the north Indian Ocean during 2000. Result shows that the MSMR-derived SST and SSWS can be utilized for several applications because of their reasonable accuracy and coverage even under cloudy condition.

Fine-measuring technique and application for sea surface wind by mobile Doppler wind lidar

The Key Laboratory of Ocean Remote Sensing of the Ministry of Education of China, Ocean University of China, has developed the first mobile Doppler wind lidar in China. As an important component of meteorological services for the Good Luck Beijing 2007 Qingdao International Regatta, the mobile Doppler wind lidar was used to measure the sea surface wind (SSW) with 100 m*100 m spatial and 10-min temporal resolution in Qingdao from 15 to 23 August 2007. We present the results from two aspects of this campaign. First, the lidar was operated in the fixed-direction mode and compared to SSW simultaneously measured by a collocated buoy. Second, we present lidar wind measurements throughout the regatta and show good agreement with the match situation of the International Regatta. In addition, we present a case study, accounting for the observation of sailboats stopped by the headwind. With considerable data accumulated, we have shown that the mobile Doppler wind lidar can indeed provide near real-time SSW in support of the sailing games. The lidar has also provided meteorological services for the 2008 Olympic sailing games from 8 to 22 August and Paralympics Sailing Games from 8 to 13 September 2008 in Qingdao.

Field detection of chlorophyll-a concentration in the sea surface layer by an airborne oceanographic lidar

An airborne oceanographic lidar, with a frequency-tripled Q-switched Nd: YAG laser of 355 nm, has been designed to measure chlorophyll-a (Chl-a) concentration in the sea surface layer by the Ocean Remote Sensing Institute, OUC. The field experi- ment was carried out in the bay which is located south of the Liaodong Peninsula on the 10th of September 2005. After the flight, the raw data were processed and analyzed by the fluorescence-to-Raman ratio method with seawater attenuation coefficients calculated from signal profiles. The results of Chl-a concentration measurements by lidar are shown. The measurements in clear sea water were also compared with those of Chl-a concentration by a Moderate Resolution Imaging Spectroradiometer (MODIS).

Comparison of visibility measurements over horizontal path by Micro-pulsed lidar and visibility meter

As a powerful tool to scan the atmosphere, the lidar can derive visibility values by directly collecting the backscattering laser light from the atmosphere. Simultaneous measurements of atmospheric visibility by Micro-pulsed lidar (MPL) and a commercial visibility meter (VM) NQ-1 have been performed to evaluate the feasibility of the MPL system designed by the Ocean Remote Sensing Laboratory (ORSL) of the Ocean University of China (OUC) from October 21 2005 to November 21 2005 in the Shilaoren Sightseeing Garden on the Qingdao coast. All the 880 data samples obtained by the two instruments have high correlation coefficients (up to 0.86), which indicates it is feasible to utilize MPL to measure atmospheric visibility.

Wind measurements with incoherent Doppler lidar based on iodine filters at night and day

An incoherent Doppler wind lidar based on the iodine filter at 532 nm is presented for day and night wind measurements, which was developed by the Key Laboratory of Ocean Remote Sensing of Ministry of Education of China, Ocean University of China. The system operates with a fiber and a narrow-band interference filter to reject daylight. A photon counter is used to improve the detection range. Two iodine filters are used to lock the transmitting laser frequency and to discriminate the Doppler frequency shift, respectively. The method to retrieve the wind profile is described. The detection range of wind profiles (with a 136 m vertical resolution) extends from 100 m to 15 km at night and to 12 km during daytime. The detection range covers the troposphere in the middle and high latitude areas. The comparison experiments between the lidar and radiosonde were performed both during the night and during the day. The standard deviation of the wind direction and speed were 15.5° and 3.1 m/s at night and 15.7° and of 3.2 m/s during the day. This system also has the capability to measure the aerosol backscattering ratio.

A Rotating Knife-beam Altimeter for Wide-swath Remote Sensing of Ocean: Wind and Waves

The use of a nadir altimeter radar with a rotating knife-beam antenna pattern isconsidered for improved measurements of the sea surface wind and wave parameters over awide swath. Theoretical calculations suggest the antenna beam rotating about the verticalaxis is able to provide wide swath of order 250-350 km. Processing of the signals using timeor Doppler sampling techniques results in the division of the antenna footprint intoelementary scattering cells of the order of 14x14 km. The theoretical algorithms developedhere indicate that the system may be used to retrieve the variance of large-scale slopes, thedirection of wave propagation and the wind speed in each cell. The possibility of measuringsignificant wave height is also analyzed. The combination of linear motion of the radar andthe rotation of the knife-beam antenna can be exploited to build up a two-dimensional mapof the surface, which enables better understanding of wave processes and to study theirstructure and temporal dynamics using repeated observations.

Future Directions in Ocean Remote Sensing

Enormous advances in ocean science and applications have already occurred in part because of the emergence of remote sensing. This paper is an informal set of general predictions about the future of ocean remote sensing. Future directions will include changes in emphasis between equities and the evolution of sensor technologies, and in platforms. There will be more emphasis and capability in coastal remote sensing and in applications oriented toward commerce, natural resources exploitation and environmental stewardship. There will be the operationalization and continued evolution of special purpose ocean remote sensing satellites and of the sensor systems on weather satellite systems. This evolution will be toward both more capability and toward enabling these assets to increase the number and type of measurements from core sensors. New ocean remote sensing platforms will emerge that are either more appropriate to emerging sensor systems or to coastal applications. These will include aircraft and geosynchronous satellite systems for LIDAR, passive microwave, and hyperspectral sensors but will also include commercial imaging satellites.

Frank S. Marzano and Guido Visconti: Remote Sensing of Atmosphere and Ocean from Space: Models, Instruments and Techniques

Frank S. Marzano and Guido Visconti: Remote Sensing of Atmosphere and Ocean from Space: Models, Instruments and Techniques

Present State and Future Prospect in Ocean Remote Sensing

Present State and Future Prospect in Ocean Remote Sensing

Low-altitude atmospheric wind measurement from the combined Mie and Rayleigh backscattering by Doppler lidar with an iodine filter.

This paper briefly discusses the mobile ground-based incoherent Doppler wind lidar system, with iodine filters as receiving frequency discriminators, developed by the Ocean Remote Sensing Laboratory, Ocean University of Qingdao, China. The presented result of wind profiles in October and November 2000, retrieved from the combined Mie and Rayleigh backscattering, is the first report to our knowledge of wind measurements in the troposphere by such a system, where the required independent measurement of aerosol-scattering ratio can also be performed. A second iodine vapor filter was used to lock the laser to absolute frequency reference for both wind and aerosol-scattering ratio measurements. Intercomparison experiments of the lidar wind profile measurements were performed with pilot balloons. Results showed that the standard deviation of wind speed and wind direction, for the 2-4 km altitude range, were 0.985 m/s and 17.9 degrees, respectively.

The Application of Reflected GPS Signals to Ocean Remote Sensing

The L-band broadcast signal from the Global Positioning System (GPS) reflected off of the sea surface is under study for use as a ocean, coastal, and wetlands remote sensing tool. The reflected signal from a given GPS satellite is cross-correlated with the pseudorandom noise code uniquely identifying that satellite. The shape of this cross-correlation, ordinarily a very sharp triangle when tracking a direct line of sight signal, becomes wider and smoother as the mean square slope of the reflecting surface increases. It is proposed that the surface wind speed can be determined by matching the recorded shape of this cross-correlation to that predicted by theoretical models as a function of wind speed and direction. The significance of these effects increases with altitude of the receiver. Experimental data have been collected using a specially modified GPS receiver on aircraft and on a balloon at altitudes of up to 25 km. These data compare favorably with predictions of analytical models and demonstrate the dependence of the waveform shape on surface wind speed and receiver altitude. The advantages that this measurement technique has over conventional scatterometers is the small size, low cost and simplicity of the receiver hardware, no requirement for a transmitter, and the ability to simultaneously collect data from usually 10 or more points (from a low earth-orbiting satellite). This number could be larger if the Russian Global Navigation Satellite System satellites are also considered as additional sources of radiation. Furthermore, the bistatic scattering geometry is complementary to the backscatter used by conventional scatterometers.