Wavelet-Based Detection of Time-Frequency Changes for Monthly Rainfall and SPI Series in Taiwan

Jenq-Tzong Shiau, Yun Feng Chiu

Research output: Contribution to journalArticle

Abstract

This study aims to assess time-frequency changes and trends of both monthly rainfall and SPI (standardized precipitation index) series in Taiwan using wavelet transform and Mann-Kendall test. The monthly data at Taipei, Sunmoon Lake, Kaohsiung, and Dawu stations with recorded length of 118, 73, 83, and 75 years, respectively, are used. The results of MK test reveal that insignificant positive monotonic trends for both rainfall and SPI series at west-side Taiwan (Taipei, Sunmoon Lake, and Kaohsiung stations) are observed, while both series have significant negative trends at Dawu station located at southeastern Taiwan. Wavelet analyses on the rainfall and SPI series indicate similar variation of wavelet power spectrum over time except the noticeable one-year periodicity in rainfall series and less power spectrum in SPI series. It is worth to note that the sub-decadal 36- and 96-month periodicities are common, but insignificant, at four stations for both series, although different data lengths are used. Combined with MK-test and wavelet-analysis results reveal that slightly less severe and less frequent droughts occur at Taipei and Sunmoon Lake stations, while drought frequencies probably remain unchanged at Kaohsiung and Dawu stations with slightly less severe and more severe droughts respectively occur at these two stations.

Original languageEnglish
Pages (from-to)657-667
Number of pages11
JournalAsia-Pacific Journal of Atmospheric Sciences
Volume55
Issue number4
DOIs
Publication statusPublished - 2019 Nov 1

Fingerprint

wavelet
rainfall
drought
periodicity
lake
wavelet analysis
detection
index
station
transform
test
trend

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Cite this

@article{1b735fd0f6f94e2c888389c86228cc8b,
title = "Wavelet-Based Detection of Time-Frequency Changes for Monthly Rainfall and SPI Series in Taiwan",
abstract = "This study aims to assess time-frequency changes and trends of both monthly rainfall and SPI (standardized precipitation index) series in Taiwan using wavelet transform and Mann-Kendall test. The monthly data at Taipei, Sunmoon Lake, Kaohsiung, and Dawu stations with recorded length of 118, 73, 83, and 75 years, respectively, are used. The results of MK test reveal that insignificant positive monotonic trends for both rainfall and SPI series at west-side Taiwan (Taipei, Sunmoon Lake, and Kaohsiung stations) are observed, while both series have significant negative trends at Dawu station located at southeastern Taiwan. Wavelet analyses on the rainfall and SPI series indicate similar variation of wavelet power spectrum over time except the noticeable one-year periodicity in rainfall series and less power spectrum in SPI series. It is worth to note that the sub-decadal 36- and 96-month periodicities are common, but insignificant, at four stations for both series, although different data lengths are used. Combined with MK-test and wavelet-analysis results reveal that slightly less severe and less frequent droughts occur at Taipei and Sunmoon Lake stations, while drought frequencies probably remain unchanged at Kaohsiung and Dawu stations with slightly less severe and more severe droughts respectively occur at these two stations.",
author = "Jenq-Tzong Shiau and Chiu, {Yun Feng}",
year = "2019",
month = "11",
day = "1",
doi = "10.1007/s13143-019-00118-9",
language = "English",
volume = "55",
pages = "657--667",
journal = "Asia-Pacific Journal of Atmospheric Sciences",
issn = "1976-7633",
publisher = "Korean Meteorological Society",
number = "4",

}

Wavelet-Based Detection of Time-Frequency Changes for Monthly Rainfall and SPI Series in Taiwan. / Shiau, Jenq-Tzong; Chiu, Yun Feng.

In: Asia-Pacific Journal of Atmospheric Sciences, Vol. 55, No. 4, 01.11.2019, p. 657-667.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Wavelet-Based Detection of Time-Frequency Changes for Monthly Rainfall and SPI Series in Taiwan

AU - Shiau, Jenq-Tzong

AU - Chiu, Yun Feng

PY - 2019/11/1

Y1 - 2019/11/1

N2 - This study aims to assess time-frequency changes and trends of both monthly rainfall and SPI (standardized precipitation index) series in Taiwan using wavelet transform and Mann-Kendall test. The monthly data at Taipei, Sunmoon Lake, Kaohsiung, and Dawu stations with recorded length of 118, 73, 83, and 75 years, respectively, are used. The results of MK test reveal that insignificant positive monotonic trends for both rainfall and SPI series at west-side Taiwan (Taipei, Sunmoon Lake, and Kaohsiung stations) are observed, while both series have significant negative trends at Dawu station located at southeastern Taiwan. Wavelet analyses on the rainfall and SPI series indicate similar variation of wavelet power spectrum over time except the noticeable one-year periodicity in rainfall series and less power spectrum in SPI series. It is worth to note that the sub-decadal 36- and 96-month periodicities are common, but insignificant, at four stations for both series, although different data lengths are used. Combined with MK-test and wavelet-analysis results reveal that slightly less severe and less frequent droughts occur at Taipei and Sunmoon Lake stations, while drought frequencies probably remain unchanged at Kaohsiung and Dawu stations with slightly less severe and more severe droughts respectively occur at these two stations.

AB - This study aims to assess time-frequency changes and trends of both monthly rainfall and SPI (standardized precipitation index) series in Taiwan using wavelet transform and Mann-Kendall test. The monthly data at Taipei, Sunmoon Lake, Kaohsiung, and Dawu stations with recorded length of 118, 73, 83, and 75 years, respectively, are used. The results of MK test reveal that insignificant positive monotonic trends for both rainfall and SPI series at west-side Taiwan (Taipei, Sunmoon Lake, and Kaohsiung stations) are observed, while both series have significant negative trends at Dawu station located at southeastern Taiwan. Wavelet analyses on the rainfall and SPI series indicate similar variation of wavelet power spectrum over time except the noticeable one-year periodicity in rainfall series and less power spectrum in SPI series. It is worth to note that the sub-decadal 36- and 96-month periodicities are common, but insignificant, at four stations for both series, although different data lengths are used. Combined with MK-test and wavelet-analysis results reveal that slightly less severe and less frequent droughts occur at Taipei and Sunmoon Lake stations, while drought frequencies probably remain unchanged at Kaohsiung and Dawu stations with slightly less severe and more severe droughts respectively occur at these two stations.

UR - http://www.scopus.com/inward/record.url?scp=85064706823&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064706823&partnerID=8YFLogxK

U2 - 10.1007/s13143-019-00118-9

DO - 10.1007/s13143-019-00118-9

M3 - Article

AN - SCOPUS:85064706823

VL - 55

SP - 657

EP - 667

JO - Asia-Pacific Journal of Atmospheric Sciences

JF - Asia-Pacific Journal of Atmospheric Sciences

SN - 1976-7633

IS - 4

ER -