10-m Level Research Articles

Experimental Investigation and Validation of Measured Wind Turbine Noise Characteristics using Standardized Technology

This paper aims in affirming the accuracy and consistency of acoustic noise assessment at an experimental and Grid Connected wind turbine. The experimental turbine is a three-bladed, upwind turbine located in the Tuticorin District of Tamil Nadu State in India. The measurement campaign was carried out during the noise measurement equipment by Brüel & Kjær (B&K) PULSE Wind Turbine Sound Power Determination system strictly in accordance with the IEC 61400-11 2012-11 AMDI 2018 Ed.3.1. The Experimental study deals in the measurement of total noise emitted from various wind turbine component and sub-systems, when the turbine is in ON condition. The background noise was obtained while the turbine is in OFF condition. The measurement data was obtained as per the above referred standards for wind speeds ranging from 7m/s to 13.5 m/s at 50m hub height. The measurement was also obtained simultaneously at 10m height above ground level for the wind speed ranging 6m/s to 8m/s during the windy season of September 2022. The measurement data both at turbine hub height and 10m level were obtained at the same atmospheric condition 26o C and 0.996atm and in a down wind direction. The other parameters like Aweighted sound pressure level, 1/3 octave band spectrum, electric power, and wind speed were also measured at both hub heights at 10m level. The measured parameters were compared with the PULSE Software output and in the process; it is concluded that the noise characteristic of the experimental wind turbine is less than 3dB at a distance of 66m in the down wind direction from the test turbine. The measured results were also validated from the PULSE software and the results show a close match.

Diagnosis of Antarctic Blowing Snow Properties Using MERRA-2 Reanalysis with a Machine Learning Model

Abstract This paper presents work using a machine learning model to diagnose Antarctic blowing snow (BLSN) properties with the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), data. We adopt the random forest classifier for BLSN identification and the random forest regressor for BLSN optical depth and height diagnosis. BLSN properties observed from the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are used as the truth for training the model. Using MERRA-2 fields such as snow age, surface elevation and pressure, temperature, specific humidity, and temperature gradient at the 2-m level, and wind speed at the 10-m level as input, reasonable results are achieved. Hourly blowing snow property diagnostics are generated with the trained model. Using 2010 as an example, it is shown that the Antarctic BLSN frequency is much higher over East than West Antarctica. High-frequency months are from April to September, during which BLSN frequency exceeds 20% over East Antarctica. For May 2010, the BLSN snow frequency in the region is as high as 37%. Due to the suppression by strong surface-based inversions, larger values of BLSN height and optical depth are usually limited to the coastal regions, wherein the strength of surface-based inversions is weaker.

A novel deep learning approach for typhoon-induced storm surge modeling through efficient emulation of wind and pressure fields

Modeling typhoon-induced storm surges requires 10-m wind and sea level pressure fields as forcings, commonly obtained using parametric models or a fully dynamical simulation by numerical weather prediction (NWP) models. The parametric models are generally less accurate than the full-physics models of the NWP, but they are often preferred owing to their computational efficiency facilitating rapid uncertainty quantification. Here, we propose using a deep learning method based on generative adversarial networks (GAN) to translate the parametric model outputs into a more realistic atmospheric forcings structure resembling the NWP model results. Additionally, we introduce lead-lag parameters to incorporate a forecasting feature in our model. Thirty-four historical typhoon events from 1981 to 2012 are selected to train the GAN, followed by storm surge simulations for the four most recent events. The proposed method efficiently transforms the parametric model into realistic forcing fields by a standard desktop computer within a few seconds. The results show that the storm surge model accuracy with forcings generated by GAN is comparable to that of the NWP model and outperforms the parametric model. Our novel GAN model offers an alternative for rapid storm forecasting and can potentially combine varied data, such as those from satellite images, to improve the forecasts further.

Evaluation of Marine Wind Profiles in the North Sea and Norwegian Sea Based on Measurements and Satellite-Derived Wind Products

The wind conditions at oil platforms are typically measured at 40–140-m height, and then reduced to standard 10-m height before being distributed via the Global Telecommunication System. The 10-m values are further used for assimilation and verification of weather forecasts models. An accurate representation of the wind profile is therefore essential. Here five wind profiles; power law, Norsok, logarithmic, Monin-Obukhov and Gryning are studied to find the best method for reduction of platform wind speeds to 10-m height level. Observations from nine oil platforms are used together with 10-m wind speed from ASCAT for evaluation of the wind profiles. In addition the wind profiles are evaluated using observations from the FINO3 offshore mast outside Denmark. The present wind profile used for wind reduction at the oil platforms (power law with a constant wind-shear coefficient of 0.13) underestimates the 10-m wind speed by as much as 0.8 m/s on average. For near neutral atmospheric stability the Norsok and the logarithmic wind profiles yield on average a near perfect fit with a wind shear coefficient of 0.085. However, 10-m wind speeds are underestimated for unstable and overestimated for stable conditions. The Monin-Obukhov and Gryning wind profiles give the most accurate estimates of 10-m wind speed during unstable and near-neutral conditions. For stable situations the Gryning wind profile, which also includes information about height of the boundary layer, gives the best agreement, but still an underestimation of the low level wind speed is encountered. The results strongly underline that atmospheric stability needs to be taken into account. For future wind reduction from observation level to 10 meter, it is recommended to use a method which takes stability into account, for example the Gryning method. For long-term average assessments however, the logarithmic and Norsok wind profiles are sufficient.

A Scalable Framework for Map Matching Based Cooperative Localization.

Localization based on scalar field map matching (e.g., using gravity anomaly, magnetic anomaly, topographics, or olfaction maps) is a potential solution for navigating in Global Navigation Satellite System (GNSS)-denied environments. In this paper, a scalable framework is presented for cooperatively localizing a group of agents based on map matching given a prior map modeling the scalar field. In order to satisfy the communication constraints, each agent in the group is assigned to different subgroups. A locally centralized cooperative localization method is performed in each subgroup to estimate the poses and covariances of all agents inside the subgroup. Each agent in the group, at the same time, could belong to multiple subgroups, which means multiple pose and covariance estimates from different subgroups exist for each agent. The improved pose estimate for each agent at each time step is then solved through an information fusion algorithm. The proposed algorithm is evaluated with two different types of scalar field based simulations. The simulation results show that the proposed algorithm is able to deal with large group sizes (e.g., 128 agents), achieve 10-m level localization performance with 180 km traveling distance, while under restrictive communication constraints.

A Biomimetic Adapter for Passive Self-alignment of Prosthetic Feet.

Dynamic alignment of lower limb prostheses is subjective and time-consuming. Compensatory gait strategies caused by prosthesis misalignment can negatively affect lower limb amputees who cannot access a certified prosthetist for alignment adjustments. The objective of this study is to evaluate a novel six-degrees-of-freedom passive transtibial prosthetic adapter that self-aligns during various phases of gait. This self-aligning adapter may benefit service members and veterans stationed or living far from a clinical facility. Four transtibial amputee subjects, aged 47 to 62 (mean: 55.75) years with mean weight of 163.6 lbs and mean K-level of 3.25, walked at self-selected speeds on a 10-m level walkway. Subjects walked with the self-aligning and a size- or weight-matched control adapter, assembled to a commercially available energy-storing-and-returning foot and their own socket, with 22-mm alignment perturbations in the anterior, posterior, medial, or lateral directions. Subjects were blinded to both adapter type and misalignment. Socket moments, spatiotemporal gait parameters, and subjective socket comfort were recorded. Preliminary results showed improvements in mean peak socket moments and step length differential with the self-aligning adapter across all alignments. Walking speed and prosthesis-side base of support showed little change in all configurations. Prosthesis-side stance duration and Functional Ambulation Profile Score increased with the self-aligning adapter in some alignments. Patient-reported socket comfort increased slightly with the self-aligning adapter across all misalignments. Subjects maintained similar walking speeds and experienced greater gait symmetry and reduced sagittal plane peak moments with the self-aligning adapter when exposed to misalignments. These trends suggest a benefit to transtibial amputees from a reduction in secondary gait effects from prosthesis misalignments. Additionally, a wider range of acceptable prosthesis alignments may be possible with the self-aligning adapter. Subsequent trials are underway to evaluate the self-aligning adapter in real-world environments like walking on uneven terrains, stairs, ramps, and abrupt turns.

High-fidelity comet 67P ephemeris and predictions based on Rosetta data

Because of observational biases and outgassing, comets are notoriously challenging in terms of trajectory estimation and ephemeris predictions. We used tracking data collected by ESA's Rosetta mission at 67P/Churyumov-Gerasimenko to derive 10-m level constraints on the distance between the Earth and 67P in 2014 and 2016, which, together with high-quality ground-based astrometry, provide unprecedented information on a comet's trajectory. Based on these data, we reconstruct the trajectory of 67P from 2012 to 2018 by modeling nongravitational perturbations with a rotating jet model, informed by measured physical properties of the comet. Using this trajectory reconstruction as reference, we characterize the astrometric error of publicly available optical observations of 67P and show how their quality significantly degrades with brightness and proximity to the Sun. Moreover, we assessed the accuracy of predictions made with different nongravitational perturbation models and data treatments. While each comet is unique and it is difficult to provide a general recipe, the reliability of an ephemeris can benefit from the availability of high-quality data with quantified uncertainties and can be gauged by comparing different ephemeris solutions and tracking a solution's stability and predictive performance as new observations are added to the fit.

Relationships between Sea Ice Concentration and Wind Speed over the Arctic Ocean during 1979–2015

AbstractNCEP CFSR reanalysis 6-hourly fields from 1979 to 2015 were used to investigate the relationships of sea ice concentration (SIC), atmospheric stratification, surface roughness, and wind speed at 10-m height (W10) and 850-hPa level (W850). We found that in autumn (September–November), winter (December–February), and spring (March–May) a lower SIC favors less-stable stratification and a higher W10. In autumn, the decrease in SIC is strongest, and SIC has its strongest correlation with the atmospheric stratification, W10, and the ratio of W10 and W850 (WSR). W10 and WSR have increased in autumn, and the negative trends in SIC typically are collocated with positive trends in W10 and WSR. In winter, W850 has negative trends over the Arctic Ocean, which, together with the lack of decrease of SIC in the central Arctic, has prevented W10 from increasing in winter. The winter trends are notably different from those for autumn, but the correlations are fairly similar. In autumn, winter, and spring, the negative correlation between SIC and W10 originated from the reduction of both stratification and aerodynamic surface roughness z0 with a reduction of SIC. The dependence of z0 on SIC is, however, weak in NCEP CFSR. In summer, the ratio of W10 and W850 has increased over large areas. The correlations between SIC and atmospheric variables were stronger on interannual time scales than on subseasonal time scales. The causal relationships are complicated by the two-way interaction between SIC and W10. In most cases, especially in summer, SIC increases after periods of W10 exceeding 5 m s−1.

Examination of Generation Mechanisms for an English Channel Meteotsunami: Combining Observations and Modeling

AbstractOn the morning of 23 June 2016, a 0.70-m meteotsunami was observed in the English Channel between the United Kingdom and France. This wave was measured by several tide gauges and coincided with a heavily precipitating convective system producing 10 m s−1 wind speeds at the 10-m level and 1–2.5-hPa surface pressure anomalies. A combination of precipitation rate cross correlations and NCEP–NCAR Reanalysis 1 data showed that the convective system moved northeastward at 19 ± 2 m s−1. To model the meteotsunami, the finite element model Telemac was forced with an ensemble of prescribed pressure forcings, covering observational uncertainty. Ensembles simulated the observed wave period and arrival times within minutes and wave heights within tens of centimeters. A directly forced wave and a secondary coastal wave were simulated, and these amplified as they propagated. Proudman resonance was responsible for the wave amplification, and the coastal wave resulted from strong refraction of the primary wave. The main generating mechanism was the atmospheric pressure anomaly with wind stress playing a secondary role, increasing the first wave peak by 16% on average. Certain tidal conditions reduced modeled wave heights by up to 56%, by shifting the location where Proudman resonance occurred. This shift was mainly from tidal currents rather than tidal elevation directly affecting shallow-water wave speed. An improved understanding of meteotsunami return periods and generation mechanisms would be aided by tide gauge measurements sampled at less than 15-min intervals.

Estimation of the ankle power during the terminal stance of gait using an inertial sensor.

[Purpose] The purpose of this study was to develop an assessment tool that reflects the ankle function during the terminal stance of gait using an inertial sensor. [Participants and Methods] Thirteen healthy males (20 limbs) participated in this study. All the participants were required to perform five straight-line walking trials along a 10-m level walkway. During the terminal stance phase, both the anterior-posterior and vertical accelerations were measured with an inertial sensor mounted on the fibular head. The Pythagorean theorem was used to calculate the acceleration vector. A three-dimensional gait analysis system was used for movement data acquisition. All statistical analyses were performed using IBM SPSS Statistics 24.0 for Windows. [Results] Results were obtained using the following multiple regression equation for the estimation of ankle plantar flexion power: Estimated Ankle Power=−4.689 + 0.269 × vertical acceleration + 0.104 × body weight. [Conclusion] Our novel method for gait analysis using an inertial sensor can assess the ankle power during the terminal stance phase of gait.

On Turbulent Fluxes During Strong Winter Bora Wind Events

Well known for its severity, the bora downslope windstorms have been extensively studied over the last several decades. This study focuses on the turbulence characteristics of bora at a topographically complex site near the eastern coast of the Adriatic Sea. For this purpose, a 3-month eddy-covariance dataset obtained at three levels (10, 22, 40 m) on a 60-m flux tower is used. After determining a suitable averaging time scale of 15 min using the fast Fourier transform and the ogive method, vertical fluxes of momentum and heat were calculated for 17 bora episodes. Up to a wind speed of $$12\,\mathrm {m\, s}^{-1}$$ , typical vertical profiles of momentum and heat were observed. However, for wind speeds > $$12\,\mathrm {m\, s}^{-1}$$ , several interesting observations arose. First, the nighttime heat flux at the 10-m level was often found to be positive rather negative. Second, vertical profiles of the momentum flux were larger at the 22-m level than at 10- and 40-m levels, mostly during nearly neutral to weakly stable thermal stratification. Third, these momentum flux profiles showed a large dependence on wind direction, with virtually no vertical transport of momentum for the largest observed wind speeds. For the first time, bora coherent structures have been analyzed using the so-called variable-interval time averaging (VITA) method. The method detected coherent structures in all three wind-speed components, with structure topologies similar to those observed over forest canopies. The momentum flux increase at the 22-m level, relative to the 10- and 40-m levels, is further supported by the VITA findings.

Storm surges along the Tottori coasts following a typhoon

In the present study, the after-runner surge that maximum surge height appears 15–18h later along the Tottori coasts facing the Sea of Japan/East Sea (SJES) after typhoons undergo a change in shape and intensity as extratropical cyclones is investigated using asymmetric and symmetric wind and pressure fields of Typhoon Songda (2004). For the asymmetric wind and pressure field, the Weather Research and Forecasting (WRF) model is used, while for the symmetric wind and pressure field, a parametric wind and pressure model is used. The results indicate that both models simulate fairly well the 10m level wind and the sea level pressure along the Pacific Ocean, while the WRF model shows better agreement with the observations over the SJES. Subsequently, from storm surge simulations for Typhoon Songda, it is found that using the deformed and asymmetric meteorological field of typhoon structures agrees well with observations. The study shows that the after-runner surge׳s characteristic comes from the Ekman setup in the presence of the Coriolis force over the Tottori coasts. It is critical that its behavior should be taken into account for the safety design of coastal defense structures around the Tottori coastal region.

Sensitivity of Tropical Cyclone Simulations to Parametric Uncertainties in Air–Sea Fluxes and Implications for Parameter Estimation

Abstract Tropical cyclones (TCs) are strongly influenced by fluxes of momentum and moist enthalpy across the air–sea interface. These fluxes cannot be resolved explicitly by current-generation numerical weather prediction models, and therefore must be accounted for via empirical parameterizations of surface exchange coefficients (CD for momentum and Ck for moist enthalpy). The resultant model uncertainty is examined through hundreds of convection-permitting Weather Research and Forecasting Model (WRF) simulations of Hurricane Katrina (2005) by varying four key parameters found in commonly used parameterizations of the exchange coefficient formulas. Two of these parameters effectively act as multiplicative factors for the exchange coefficients over all wind speeds (one each for CD and Ck); the other two parameters control the behavior of CD at very high wind speeds (i.e., above 33 m s−1). It is found that both the intensity and the structure of TCs are highly dependent upon the two multiplicative parameters. The multiplicative parameter for CD has a considerably larger impact than the one for Ck on the relationship between maximum 10-m wind speed and minimum sea level pressure: CD alters TC structure, with higher values shifting the radius of maximum winds inward and strengthening the low-level inflow; Ck only affects structure by uniformly strengthening/weakening the primary and secondary circulations. The TC exhibits the greatest sensitivities to the two multiplicative parameters after a few hours of model integration, suggesting that these parameters could be estimated by assimilating near-surface observations. The other two parameters are likely more difficult to estimate because the TC is only marginally sensitive to them in small areas of high wind speed.

The Track Integrated Kinetic Energy of Atlantic Tropical Cyclones

Abstract In this paper the concept of track integrated kinetic energy (TIKE) is introduced as a measure of seasonal Atlantic tropical cyclone activity and applied to seasonal variability in the Atlantic. It is similar in concept to the more commonly used accumulated cyclone energy (ACE) with an important difference that in TIKE the integrated kinetic energy (IKE) is accumulated for the life span of the Atlantic tropical cyclone. The IKE is, however, computed by volume integrating the 10-m level sustained winds of tropical strength or higher quadrant by quadrant, while ACE uses the maximum sustained winds only without accounting for the structure of the storm. In effect TIKE accounts for the intensity, duration, and size of the tropical cyclones. In this research, the authors have examined the seasonality and the interannual variations of the seasonal Atlantic TIKE over a period of 22 yr from 1990 to 2011. It is found that the Atlantic TIKE climatologically peaks in the month of September and the frequency of storms with the largest TIKE are highest in the eastern tropical Atlantic. The interannual variations of the Atlantic TIKE reveal that it is likely influenced by SST variations in the equatorial Pacific and in the Atlantic Oceans. The SST variations in the central equatorial Pacific are negatively correlated with the contemporaneous seasonal (June–November) TIKE. The size of the Atlantic warm pool (AWP) is positively correlated with seasonal TIKE.

Effects of Intramuscular Trunk Stimulation on Manual Wheelchair Propulsion Mechanics in 6 Subjects With Spinal Cord Injury

ObjectiveTo quantify the effects of stabilizing the paralyzed trunk and pelvis with electrical stimulation on manual wheelchair propulsion. DesignSingle-subject design case series with subjects acting as their own concurrent controls. SettingHospital-based clinical biomechanics laboratory. ParticipantsIndividuals (N=6; 4 men, 2 women; mean age ± SD, 46±10.8y) who were long-time users (6.1±3.9y) of implanted neuroprostheses for lower extremity function and had chronic (8.6±2.8y) midcervical- or thoracic-level injuries (C6-T10). InterventionsContinuous low-level stimulation to the hip (gluteus maximus, posterior adductor, or hamstrings) and trunk extensor (lumbar erector spinae and/or quadratus lumborum) muscles with implanted intramuscular electrodes. Main Outcome MeasuresPushrim kinetics (peak resultant force, fraction effective force), kinematics (cadence, stroke length, maximum forward lean), and peak shoulder moment at preferred speed over 10-m level surface; speed, pushrim kinetics, and subjective ratings of effort for level 100-m sprints and up a 30.5-m ramp of approximately 5% grade. ResultsThree of 5 subjects demonstrated reduced peak resultant pushrim forces (P≤.014) and improved efficiency (P≤.048) with stimulation during self-paced level propulsion. Peak sagittal shoulder moment remained unchanged in 3 subjects and increased in 2 others (P<.001). Maximal forward trunk lean also increased by 19% to 26% (P<.001) with stimulation in these 3 subjects. Stroke lengths were unchanged by stimulation in all subjects, and 2 showed extremely small (5%) but statistically significant increases in cadence (P≤.021). Performance measures for sprints and inclines were generally unchanged with stimulation; however, subjects consistently rated propulsion with stimulation to be easier for both surfaces. ConclusionsStabilizing the pelvis and trunk with low levels of continuous electrical stimulation to the lumbar trunk and hip extensors can positively impact the mechanics of manual wheelchair propulsion and reduce both perceived and physical measures of effort.

Impact of Physics Representations in the HWRFX on Simulated Hurricane Structure and Pressure–Wind Relationships

Abstract A series of idealized experiments with the NOAA Experimental Hurricane Weather Research and Forecasting Model (HWRFX) are performed to examine the sensitivity of idealized tropical cyclone (TC) intensification to various parameterization schemes of the boundary layer (BL), subgrid convection, cloud microphysics, and radiation. Results from all the experiments are compared in terms of the maximum surface 10-m wind (VMAX) and minimum sea level pressure (PMIN)—operational metrics of TC intensity—as well as the azimuthally averaged temporal and spatial structure of the tangential wind and its material acceleration. The conventional metrics of TC intensity (VMAX and PMIN) are found to be insufficient to reveal the sensitivity of the simulated TC to variations in model physics. Comparisons of the sensitivity runs indicate that (i) different boundary layer physics parameterization schemes for vertical subgrid turbulence mixing lead to differences not only in the intensity evolution in terms of VMAX and PMIN, but also in the structural characteristics of the simulated tropical cyclone; (ii) the surface drag coefficient is a key parameter that controls the VMAX–PMIN relationship near the surface; and (iii) different microphysics and subgrid convection parameterization schemes, because of their different realizations of diabatic heating distribution, lead to significant variations in the vortex structure. The quantitative aspects of these results indicate that the current uncertainties in the BL mixing, surface drag, and microphysics parameterization schemes have comparable impacts on the intensity and structure of simulated TCs. The results also indicate that there is a need to include structural parameters in the HWRFX evaluation.

Evaluation of the Added Value of Regional Ensemble Forecasts on Global Ensemble Forecasts

Abstract The regional single-model-based Aire Limitée Adaptation Dynamique Développement International–Limited Area Ensemble Forecasting (ALADIN-LAEF) ensemble prediction system (EPS) is evaluated and compared with the global ECMWF-EPS to investigate the added value of regional to global EPS models. ALADIN-LAEF consists of 16 perturbed members at 18-km horizontal resolution, while ECMWF-EPS includes 50 perturbed members at 50-km horizontal resolution. In ALADIN-LAEF, the atmospheric initial condition uncertainty is quantified by using blending, which combines large-scale uncertainty generated by the ECMWF-EPS singular-vector approach with small-scale perturbations resolved by the ALADIN breeding technique. The surface initial condition perturbations are generated by use of the noncycling surface breeding (NCSB) technique, and different physics schemes are employed for different forecast members to account for model uncertainties. The verification and comparison have been carried out for a 2-month period during summer 2007 over central Europe. The results show a quite favorable level of performance for ALADIN-LAEF compared to ECMWF-EPS for surface weather variables. ALADIN-LAEF adds more value to precipitation forecasts and has greater skill for 10-m wind and mean sea level pressure results than does ECMWF-EPS. For 2-m temperature, ALADIN-LAEF forecasts have larger spread, are statistically more consistent, but also have less skill than ECMWF-EPS due to the strong cold bias in the ALADIN forecasts. For the upper-air weather parameters, the forecast of ALADIN-LAEF has a larger spread, but the forecast skill of ALADIN-LAEF is from neutral to slightly inferior compared to ECMWF-EPS. It may be concluded that a regional single-model-based EPS with fewer ensemble members could provide more added value in terms of greater skill for near-surface weather variables than the global EPS with larger ensemble size, whereas it may have limitations when applied to upper-air weather variables.

Analysis of Local Air–Sea Interaction in East Asia Using a Regional Air–Sea Coupled Model

Abstract A regional air–sea coupled climate model based on the third regional climate model (RegCM3) and the regional oceanic model [the Princeton Ocean Model (POM)] is used to analyze the local air–sea interaction over East Asia in this study. The results indicate that the simulated sea surface temperature (SST) of the coupled model RegCM3–POM is reasonably accurate, and that the spatial pattern and temporal variation are consistent with that of the Global Sea Ice and Sea Surface Temperature dataset (GISST). The correlation between the SST and the atmospheric variables shows that the uncoupled model RegCM3 forced by the given SST cannot reproduce the real-time and SST lag correlation between SST and precipitation, and between SST and surface wind speed, whereas the relationship in the coupled model RegCM3–POM is reasonably accurate. RegCM3–POM reflects the air–sea interaction in the South China Sea and western Pacific Ocean, where the SST lead correlation is the inverse of the SST lag correlation between SST and precipitation, and strong winds bring warm water to the midlatitudes, so the correlation between wind speed and SST is negative in low latitudes and positive in the Kuroshio area. The uncoupled model fails to reproduce the effect of the atmosphere on the ocean. The further study on air–sea interaction in the South China Sea indicates that the earlier warm seawater corresponds to strong sensible heat flux, evaporation, precipitation, and weak net solar radiation, and the early strong sensible heat flux, evaporation, wind at the 10-m level, and weak net solar radiation cause the cold SST.

태풍 내습 시 3-second gust를 이용한 피해액 산정

The most efficient measures to reduce damage from natural disasters include activities which prevent disasters in advance, decrease possibility of disasters and minimize the scale of damage. Therefore, developing of the risk assessment model is very important to reduce the natural disaster damage. This study estimated a typhoon damage which is the biggest damage scale among increased natural disasters in Korea along with climate change. The results of 3-second gust at the height of 10m level from the typhoon 'Maemi' which did considerable damage to Korean in 2003, using the wind data at the height of 700 hPa. September 12th 09 LST~13th 12 LST period by the time a typhoon Maemi approached to the Korean peninsula. This study estimate damage amount using 'Fragility curve' which is the damage probability curve about a certain wind speed of the each building component factors based on wind load estimation results by using 3-second gust. But the fragility curve is not to Korea. Therefore, we use the fragility curves to FPHLM(FDFS, 2005). The result of houses damage amount is about 11 trillion 5 million won. This values are limit the 1-story detached dwelling, of total area. Therefore, this process is possible application to other type houses.

Homogenization and Trend Analysis of Canadian Near-Surface Wind Speeds

Abstract Near-surface wind speeds recorded at 117 stations in Canada for the period from 1953 to 2006 were analyzed in this study. First, metadata and a logarithmic wind profile were used to adjust hourly wind speeds measured at nonstandard anemometer heights to the standard 10-m level. Monthly mean near-surface wind speed series were then derived and subjected to a statistical homogeneity test, with homogeneous monthly mean geostrophic wind (geowind) speed series being used as reference series. Homogenized monthly mean near-surface wind speed series were obtained by adjusting all significant mean shifts, using the results of the statistical test and modeling along with all available metadata, and were used to assess the long-term trends. This study shows that station relocation and anemometer height change are the main causes for discontinuities in the near-surface wind speed series, followed by instrumentation problems or changes, and observing environment changes. It also shows that the effects of artificial mean shifts on the results of trend analysis are remarkable, and that the homogenized near-surface wind speed series show good spatial consistency of trends, which are in agreement with long-term trends estimated from independent datasets, such as surface winds in the United States and cyclone activity indices and ocean wave heights in the region. These indicate success in the homogenization of the wind data. During the period analyzed, the homogenized near-surface wind speed series show significant decreases throughout western Canada and most parts of southern Canada (except the Maritimes) in all seasons, with significant increases in the central Canadian Arctic in all seasons and in the Maritimes in spring and autumn.