一分鐘報天氣/週三(02/23日) 鋒面通過上半天留意較大
明天天氣如何?
今天(22日)冷空氣相較於前幾日有所減弱，但在華南雲系東移帶來降雨的情況下，各地仍然是陰雨的天氣型態，因此溫度並沒有回升太多，還是偏向濕濕冷冷的感覺。今晚到明天(23日)上午逐漸有鋒面系統在臺灣附近建立通過，首先會有低壓系統在東北部外海發展，東北角一帶、宜蘭北部可能會有短時較大雨勢出現，中部山區也會是降雨比較明顯的區域，而到了明天(23日)鋒面通過期間，預估中北部平地也會有一陣較大的驟雨。鋒面通過後大陸冷氣團將再帶來一波冷空氣，中北部、東北部在明天白天就會降至13-15度，南部、花東白天還有16-18度，但到了晚間也會降到14度上下。
週四開始水氣逐漸減少，除了北部、東半部地區以外，各地大致可以轉為穩定多雲到晴的好天氣，降雨會集中在迎風面北海岸到東北角以及宜蘭地區，大臺北市區的雨勢也會逐漸停緩，氣溫方面則會由濕冷轉為乾冷，入夜到隔日清晨，西半部地區雲量減少，局部可能有明顯的輻射冷卻作用發生，配合冷空氣可能會有10-11度的低溫發生，其他地方則維持在13-14度。
週五隨著大陸高壓出海，環境逐漸轉為偏東風，風速及冷空氣明顯減弱，天氣會更進一步轉好，整個西半部都是多雲到晴，東半部雲量還是偏多並有短暫陣雨，預估這樣的天氣大致可以維持到下週一，期間雖然有幾波東北風南下，但是強度大多偏弱，對臺灣影響不大，北部高溫可以回升至20度左右，中南部更是可以來到25-26度，而夜間的低溫大概回升至15-16度，因此中南部日夜的溫差變化會相當明顯，另外在偏東風環境下，西半部在清晨時容易有霧靄或低雲產生，早上較早出門的話要留意能見度較差的狀況，注意行車、交通安全。
以上氣象由 天氣風險/林琮訓 提供
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The log-periodic antenna as known as LPDA is a wideband directional antenna that provides gain and directivity combined over a wide band of frequencies.
Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas.
The log-periodic dipole array typical VSWR is 2:1 and operates over a much wider bandwidth and will have a lower gain for an equivalent number of elements.
In terms of its specification, a typical log periodic antenna might provide between 3 and 6 dB gain over dipole for a bandwidth of 2:1 while retaining a VSWR level of better than 1.3:1. With this level of performance, it is ideal for many applications, although a log-periodic antenna will be much larger than a Yagi of an equivalent gain.
EMC/EMI pre-compliance test antenna.
Very high gain over the full frequency range.
Meets latest EMC standards up to 7GHz.
Suitable even for immunity measurements
