No abstract

This study analyzed the wind speed data of the met mast in the first commercial-scale offshore wind farm of Taiwan from May 2017 to April 2018. The mean wind speed and standard deviation, wind rose, histogram, wind speed profile, and diurnal variation of wind speed with associated changes in wind direction revealed some noteworthy findings. First, the standard deviation of the corresponding mean wind speed is somewhat high. Second, the Hellmann exponent is as low as 0.05. Third, afternoons in winter and nights and early mornings in summer have the highest and lowest wind speed in a year, respectively. Regarding the histogram, the distribution probability of wind is bimodal, which can be depicted as a mixture of two gamma distributions. In addition, the corresponding change between the hourly mean wind speed and wind direction revealed that the land–sea breeze plays a significant role in wind speed distribution, wind profile, and wind energy production. The low Hellmann exponent is discussed in detail. To further clarify the effect of the land–sea breeze for facilitating future wind energy development in Taiwan, we propose some recommendations.

Taiwan’s Central Weather Bureau (CWB) has established a new version of tropical cyclone (TC) database to provide users with comprehensive TC data services. As of June 2022, the database includes 1673 TCs originating in the western North Pacific and South China Sea regions since the CWB began TC forecasting operations in 1958. It collects not only the track dataset, satellite imagery, and synoptic weather charts, but also more detailed data and products of TCs that have impacted Taiwan, such as radar reflectivity imagery, high-density surface observations, dropwindsonde data from aircraft observations, and mesoscale analysis maps of rainfall, wind, pressure, and temperature. Such detailed data realistically preserves the TC’s journey across Taiwan and is a feature of the CWB TC database. In addition, the TC database website (https://rdc28.cwb.gov.tw/TDB/) provides tools that allow users to search for TCs of interest based on track, rainfall, and wind. Digital best track data since 1958 is available (https://rdc28.cwb.gov.tw/TDB/manager/obs_data_download/) for users to download and conduct TC research. Also included are technical reports summarizing extensive historical observational research focusing on the mesoscale variations during a TC’s passage over Taiwan. The TC database has been widely used in academic research, disaster prevention, crop revenue insurance, offshore wind power, and other fields. It will continue to develop useful products and integrate more diverse observations to meet the needs of different users.

Renewable energy is crucial for achieving net zero emissions. Taiwan has abundant wind resources and most major wind farms are offshore over the Taiwan Strait due to a lack of space on land. A thorough study that includes time series modeling of wind speed and sea breeze identification and evaluation for Taiwan’s offshore wind farms was conducted. The time series modeling identified two periodic (annual and diurnal) components and an autoregressive model for multiple-year wind speed time series. A new method for sea breeze type identification and magnitude evaluation is proposed. The method (named as EACH) utilizes a vector and an ellipse to represent the wind condition of a day. Verification of the type identification determined by the new method in two cases of different seasons has been conducted by using surface weather charts and wind data measured by lidar. It is a concise, effective, and programmable way to filter a number of dates for type identification and speed change precursor of sea breeze. We found that the typical daily wind power production of corkscrew sea breeze in Central Taiwan is more than 33 times that of pure sea breeze and more than 9 times that of backdoor sea breeze, which highlights the impact of sea breeze types on wind power.

Taiwan’s Central Weather Bureau (CWB) has established a new version of tropical cyclone (TC) database to provide users with comprehensive TC data services. As of May 2022, the database includes 1,672 TCs originating in the western North Pacific and South China Sea regions since the CWB began TC forecasting operations in 1958. It collects not only the track dataset, satellite imagery, and synoptic weather charts, but also more detailed data and products of TCs that have impacted Taiwan, such as radar reflectivity imagery, high-density surface observations, dropwindsonde data from aircraft observations, and mesoscale analysis maps of rainfall, wind, pressure, and temperature. Such detailed data realistically preserves the TC’s journey across Taiwan and is a feature of the CWB TC database. In addition, the TC database website (https://rdc28.cwb.gov.tw/TDB/) provides tools that allow users to search for TCs of interest based on track, rainfall, and wind. Also included are technical reports summarizing extensive historical observational research focusing on the mesoscale variations during a TC’s passage over Taiwan. The TC database is widely used in academic research, disaster prevention, crop revenue insurance, offshore wind power, and other fields. It will continue to develop useful products and integrate more diverse observations to meet the needs of different users.