An analysis of urban heat island impact toward increasing of afternoon thunderstorm frequency in Taipei, Taiwan

2021 ◽  
Author(s):  
Siti Talitha Rachma ◽  
Yuan-Chien Lin
Keyword(s):  
Urban Heat Island ◽  
Empirical Orthogonal Function ◽  
Precipitation Pattern ◽  
Heat Island ◽  
Hilbert Huang Transform ◽  
Orthogonal Function ◽  
Hourly Temperature ◽  
Taipei City ◽  
The Future ◽  
Urban Heat

<p>Each year, average of Earth’s temperature rises and the urbanized cities, are warming at a significant rate than the surrounding rural areas. This phenomenon is called Urban Heat Island (UHI). UHI is a consequence of human activities in urban area and it has possibilities to impact weather and climate on regional or global scale. Precipitation is one of the basic hydro-meteorological phenomena that could be affected by UHI trend with thunderstorm as a part of precipitation. As the UHI level rises from year to year, the pattern of precipitation could change. However, this issue is still underdeveloped, thus, this work tries to comprehensively understand the hydrological response to UHI.</p><p> </p><p>This research selects Taipei city as the study area and explores the connection between UHI and precipitation pattern’s change. The data used here are hourly temperature and precipitation data collected from 21 Taipei weather stations collected from Central Weather Bureau (CWB) Taiwan. In order to reveal specific details and trend of non-linear relation from both time domain and frequency, Hilbert-Huang Transform (HHT) is adopted in this study. The HHT results are compared between each station. Later, empirical orthogonal function (EOF) also being used to extract main spatial pattern of precipitation in Taipei city.</p><p> </p><p>The results show that the urbanization in Taipei city contribute to increasing trend of 0.5 – 1 <sup>o</sup>C in daily UHI and also increase of 27% in the afternoon thunderstorm frequency for this past 20 years. The increase of thunderstorm would result into a bigger rain water flow to the river and a fewer time for it to percolate to the ground. If there are more thunderstorms in the future, it is possible the phenomenon could lead to the lack of groundwater discharge and depletion of groundwater reserve. This result could be utilized in the future to understand more about UHI mitigation and thunderstorm in Taipei.</p><p> </p><p>Keywords: urban heat island, thunderstorm, Hilbert-Huang Transform, empirical orthogonal function</p>

scholarly journals Spatial Superposition Method via Model Coupling for Urban Heat Island Albedo Mitigation Strategies

2012 ◽  
Vol 51 (11) ◽  
pp. 1971-1979 ◽  
Author(s):  
Humberto Silva ◽  
Jay S. Golden
Keyword(s):  
Urban Heat Island ◽  
Mesoscale Model ◽  
Coupled Model ◽  
Mitigation Strategies ◽  
Turbulence Theory ◽  
Superposition Method ◽  
Heat Island ◽  
Lumped Model ◽  
Hourly Temperature ◽  
Urban Heat

AbstractA spatial superposition design is presented that couples the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) with the National Center of Excellence (NCE) lumped urban thermal model for application to the city of Phoenix, Arizona. This technique utilizes an approach similar to Reynolds decomposition from turbulence theory. The presented decomposition takes the NCE model prediction from a mitigated strategy as the mean temperature and the difference between the NCE and MM5 predictions without mitigation strategy as the perturbed temperature. The goal of this coupled model is to provide spatial variability when simulating mitigation strategies for the urban heat island effect, as compared with the spatially invariant lumped model. A validation analysis was performed incorporating a maximum 35% change from the baseline albedo value for the urban environment. It is shown that the coupled model differs by up to 0.39°C with comparable average surface temperature predictions from MM5. The coupled model was also used to perform analysis of three different albedo-driven spatial mitigation schemes. This resulted in the identification that having a lesser number of mitigated points on a square urban grid in Phoenix with the same average albedo leads to a greater reduction in average hourly temperature.

scholarly journals Impact of urbanization on thermal environment of Chengdu-Chongqing Urban Agglomeration under complex terrain

2021 ◽  
Author(s):  
Si Chen ◽  
Zhenghui Xie ◽  
Jinbo Xie ◽  
Bin Liu ◽  
Binghao Jia ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Urban Area ◽  
Complex Terrain ◽  
Thermal Environment ◽  
Urban Agglomeration ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Island Effect ◽  
The Future ◽  
Urban Heat

Abstract. Located in the mountainous area of southwest China, the Chengdu-Chongqing Urban Agglomeration (CCUA) was rapidly urbanized in the last four decades, has led to a three-fold urban area expansion, thereby affecting the weather and climate. To investigate the urbanization effects on the thermal environment in the CCUA under the complex terrain, we conducted the simulations using the advanced Weather Research and Forecasting (WRF V4.1.5) model together with the combining land-use scenarios and terrain conditions. We observed that the WRF model reproduces the general synoptic summer weather pattern, particularly for the thermal environment. It was shown that the expansion of the urban area changed the underlying surface's thermal properties, leading to the urban heat island effect, enhanced by the complex terrain further. The simulation with the future scenario shows that the implementation of idealized measures including returning farmland to forests, expanding rivers and lakes can reduce the urban heat island effect and regulate the urban ecosystem. Therefore, the urban planning policy can has potential to provide feasible suggestions to best manage the thermal environment of the future city toward improving the livelihood of the people in the environment.

Analisis Pengaruh Kerapatan Vegetasi Terhadap Suhu Permukaan dan Keterkaitannya Dengan Fenomena UHI

2020 ◽  
Vol 21 (1) ◽  
pp. 99
Author(s):  
Dewi Miska Indrawati ◽  
Suharyadi Suharyadi ◽  
Prima Widayani
Keyword(s):  
Urban Heat Island ◽  
Landsat 8 ◽  
Heat Island ◽  
Landsat 8 Oli ◽  
Urban Heat ◽  
Split Window Algorithm

Kota Mataram adalahpusat dan ibukota dari provinsi Nusa Tenggara Barat yang tentunya menjadi pusat semua aktivitas masyarakat disekitar daerah tersebut sehingga menyebabkan peningkatan urbanisasi. Semakin meningkatnya peningkatan urbanisasi yan terjadi di perkotaan akan menyebabkan perubahan penutup lahan, dari awalnya daerah bervegetasi berubah menjadi lahan terbangun. Oleh karena itu, akan memicu peningkatan suhu dan menyebabkan adanya fenomena UHI dikota Mataram.Tujuan dari penelitian ini untuk mengetahui hubungan kerapatan vegetasi dengan kondisi suhu permukaan yang ada diwilayah penelitian dan memetakan fenomena UHI di Kota Mataram. Citra Landsat 8 OLI tahun 2018 yang digunakan terlebih dahulu dikoreksi radiometrik dan geometrik. Metode untuk memperoleh data kerapatan vegetasi menggunakan transformasi NDVI, LST menggunakan metode Split Window Algorithm (SWA) dan identifikasi fenomena urban heat island. Hasil penelitian yang diperoleh menunjukkan kerapatan vegetasi mempunyai korelasi dengan nilai LST. Hasil korelasi dari analisis pearson yang didapatkan antara kerapatan vegetasi terhadap suhu permukaan menghasilkan nilai -0,744. Fenomena UHIterjadi di pusat Kota Mataram dapat dilihat dengan adanya nilai UHI yaitu 0-100C. Semakin besar nilai UHI, semakin tinggi perbedaan LSTnya.

PERUBAHAN PENUTUP LAHAN DAN KERAPATAN VEGETASI TERHADAP URBAN HEAT ISLAND DI KOTA SURAKARTA

2019 ◽  
Vol 3 ◽  
pp. 641
Author(s):  
Nafisatul Baroroh ◽  
Pangi Pangi
Keyword(s):  
Urban Heat Island ◽  
Heat Island ◽  
Urban Heat

Secara fisik, perkembangan perkotaan dapat terlihat dari perubahan penduduknya yang semakin bertambah dan semakin padat. Menurut data Badan Pusat Statistik, jumlah penduduk Kota Surakarta tahun 2000 yaitu sebesar 490.214 jiwa dan meningkat ±23.957 jiwa di tahun 2016. Pertumbuhan penduduk dan pembangunan yang pesat akan menyebabkan perubahan penggunaan lahan demi menunjang aktifitas penduduk yang seringkali mengakibatkan benturan kepentingan sehingga mengakibatkan menurunnya kualitas lingkungan. Hal itu disebabkan oleh semakin terdesaknya alokasi lahan untuk vegetasi. Perubahan lahan vegetasi yang tergantikan oleh jalan, bangunan dan struktur lain akan lebih banyak menyerap panas matahari dan memantulkannya, sehingga menyebabkan suhu permukaan di kota naik. Akibatnya semakin banyak titik-titik panas yang terbentuk sehingga menyebabkan perubahan unsur-unsur cuaca dan iklim sebagai pemicu terjadinya Urban Heat Island (UHI). Sesuai dengan uraian tersebut, maka tujuan penelitian ini adalah untuk menganalisis perubahan penutup lahan dan kerapatan vegetasi terhadap Urban Heat Island di Kota Surakarta. Metode analisis yang digunakan yaitu analisis deskriptif dan pengolahan data spasial. Berdasarkan hasil dari analisis menunjukkan bahwa jenis penutup lahan yang mendominasi adalah permukiman dan lahan terbangun, serta kelas kerapatan vegetasi didominasi oleh vegetasi jarang. Kemudian untuk distribusi suhu permukaan di Kota Surakarta secara keseluruhan tahun 1994, 2000 dan 2017 nilainya berubah, dimana rentang suhunya berkisar antara 21 C – 24 C (terendah) sampai dengan 34 C – 37 C (tertinggi). Perubahan suhu yang terjadi inilah mengindikasikan terjadinya fenomena Urban Heat Island di Kota Surakarta. Berdasarkan hal tersebut, maka dapat disumpulkan bahwa terdapat perubahan jenis penutup lahan dan juga kelas kerapatan vegetasi yang terjadi terhadap Urban Heat Island di Kota Surakarta.

OVERVIEW OF URBAN HEAT ISLAND (UHI) PHENOMENON TOWARDS HUMAN THERMAL COMFORT

2017 ◽  
Vol 16 (9) ◽  
pp. 2097-2111 ◽  
Author(s):  
Mohanadoss Ponraj ◽  
Yee Yong Lee ◽  
Mohd Fadhil Md Din ◽  
Zainura Zainon Noor ◽  
Kenzo Iwao ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Heat Island ◽  
Human Thermal Comfort ◽  
Urban Heat
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