scholarly journals Covarying Hydroclimate Patterns between Monsoonal Asia and North America over the Past 600 Years

2014 ◽  
Vol 27 (21) ◽  
pp. 8017-8033 ◽  
Author(s):  
Keyan Fang ◽  
Deliang Chen ◽  
Jinbao Li ◽  
Heikki Seppä
Keyword(s):  
North America ◽  
Southern Oscillation ◽  
Severity Index ◽  
Drought Severity ◽  
Solar Forcing ◽  
The Past ◽  
Spatial Coverage ◽  
Dipole Pattern ◽  
Value Decomposition ◽  
Svd Method

Abstract Proxy data with large spatial coverage spanning to the preindustrial era not only provide invaluable material to investigate hydroclimate changes in different regions but also enable studies on temporal changes in the teleconnections between these regions. Applying the singular value decomposition (SVD) method to tree-ring-based field reconstructions of the Palmer drought severity index (PDSI) over monsoonal Asia (MA) and North America (NA) from 1404 to 2005, the dominant covarying pattern between the two regions is identified. This pattern is represented by the teleconnection between the dipole pattern of southern–northern latitudinal MA and the dipole of southwest NA (SWNA)–northwest NA (NWNA), which accounts for 59.6% of the total covariance. It is dominated by an antiphase low MA and SWNA teleconnection, driven by the El Niño–Southern Oscillation (ENSO), and is most significant at an interannual time scale. This teleconnection is strengthened (weakened) in periods of increased (decreased) solar forcing and high (low) temperature, which is associated with intensified (weakened) ENSO variability. Additional forcing by SST anomalies in the Indian and western Pacific Oceans appears to be important too.

scholarly journals Moisture and Temperature Covariability over the Southeastern Tibetan Plateau during the Past Nine Centuries

2020 ◽  
Vol 33 (15) ◽  
pp. 6583-6598
Author(s):  
Jianglin Wang ◽  
Bao Yang ◽  
Fredrik Charpentier Ljungqvist
Keyword(s):  
Tibetan Plateau ◽  
Climate Model ◽  
Severity Index ◽  
Early Summer ◽  
Convective Precipitation ◽  
Drought Severity ◽  
The Tibetan Plateau ◽  
Low Frequencies ◽  
The Past ◽  
Spatial Coverage

AbstractAccurate projections of moisture variability across the Tibetan Plateau (TP) are crucial for managing regional water resources, ecosystems, and agriculture in densely populated downstream regions. Our understanding of how moisture conditions respond to increasing temperatures over the TP is still limited, due to the short length of instrumental data and the limited spatial coverage of high-resolution paleoclimate proxy records in this region. This study presents a new, early-summer (May–June) self-calibrating Palmer drought severity index (scPDSI) reconstruction for the southeastern TP (SETP) covering 1135–2010 CE using 14 tree-ring records based on 1669 individual width sample series. The new reconstruction reveals that the SETP experienced the longest period of pluvial conditions in 1154–75 CE, and the longest droughts during the periods 1262–80 and 1958–76 CE. The scPDSI reconstruction shows stable and significant in-phase relationships with temperature at both high and low frequencies throughout the past 900 years. This supports the hypothesis that climatic warming may increase moisture by enhancing moisture recycling and convective precipitation over the SETP; it is also consistent with climate model projections of wetter conditions by the late twenty-first century in response to global warming.

scholarly journals A 424-year tree-ring-based Palmer Drought Severity Index reconstruction of <i>Cedrus deodara</i> D. Don from the Hindu Kush range of Pakistan: linkages to ocean oscillations

2020 ◽  
Vol 16 (2) ◽  
pp. 783-798
Author(s):  
Sarir Ahmad ◽  
Liangjun Zhu ◽  
Sumaira Yasmeen ◽  
Yuandong Zhang ◽  
Zongshan Li ◽  
...  
Keyword(s):  
Tree Ring ◽  
Palmer Drought Severity Index ◽  
Southern Oscillation ◽  
Ring Width ◽  
Severity Index ◽  
Drought Severity ◽  
Mountain Range ◽  
Cedrus Deodara ◽  
Hindu Kush ◽  
Drought Severity Index

Abstract. The rate of global warming has led to persistent drought. It is considered to be the preliminary factor affecting socioeconomic development under the background of the dynamic forecasting of the water supply and forest ecosystems in West Asia. However, long-term climate records in the semiarid Hindu Kush range are seriously lacking. Therefore, we developed a new tree-ring width chronology of Cedrus deodara spanning the period of 1537–2017. We reconstructed the March–August Palmer Drought Severity Index (PDSI) for the past 424 years, going back to 1593 CE. Our reconstruction featured nine dry periods (1593–1598, 1602–1608, 1631–1645, 1647–1660, 1756–1765, 1785–1800, 1870–1878, 1917–1923, and 1981–1995) and eight wet periods (1663–1675, 1687–1708, 1771–1773, 1806–1814, 1844–1852, 1932–1935, 1965–1969, and 1990–1999). This reconstruction is consistent with other dendroclimatic reconstructions in West Asia, thereby confirming its reliability. The multi-taper method and wavelet analysis revealed drought variability at periodicities of 2.1–2.4, 3.3, 6.0, 16.8, and 34.0–38.0 years. The drought patterns could be linked to the large-scale atmospheric–oceanic variability, such as the El Niño–Southern Oscillation, Atlantic Multidecadal Oscillation, and solar activity. In terms of current climate conditions, our findings have important implications for developing drought-resistant policies in communities on the fringes of the Hindu Kush mountain range in northern Pakistan.

scholarly journals Juniper Tree-Ring Data from the Kuramin Range (Northern Tajikistan) Reveals Changing Summer Drought Signals in Western Central Asia

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 505 ◽  
Author(s):  
Feng Chen ◽  
Tongwen Zhang ◽  
Andrea Seim ◽  
Shulong Yu ◽  
Ruibo Zhang ◽  
...  
Keyword(s):  
Central Asia ◽  
Tree Ring ◽  
Large Scale ◽  
Southern Oscillation ◽  
Severity Index ◽  
Drought Severity ◽  
Summer Drought ◽  
Tree Ring Chronology ◽  
Tree Ring Data ◽  
June July

Coniferous forests cover the mountains in many parts of Central Asia and provide large potentials for dendroclimatic studies of past climate variability. However, to date, only a few tree-ring based climate reconstructions exist from this region. Here, we present a regional tree-ring chronology from the moisture-sensitive Zeravshan juniper (Juniperus seravschanica Kom.) from the Kuramin Range (Tajikistan) in western Central Asia, which is used to reveal past summer drought variability from 1650 to 2015 Common Era (CE). The chronology accounts for 40.5% of the variance of the June–July self-calibrating Palmer Drought Severity Index (scPDSI) during the instrumental period (1901 to 2012). Seven dry periods, including 1659–1696, 1705–1722, 1731–1741, 1758–1790, 1800–1842, 1860–1875, and 1931–1987, and five wet periods, including 1742–1752, 1843–1859, 1876–1913, 1921–1930, and 1988–2015, were identified. Good agreements between drought records from western and eastern Central Asia suggest that the PDSI records retain common drought signals and capture the regional dry/wet periods of Central Asia. Moreover, the spectral analysis indicates the existence of centennial (128 years), decadal (24.3 and 11.4 years), and interannual (8.0, 3.6, 2.9, and 2.0 years) cycles, which may be linked with climate forces, such as solar activity and El Niño-Southern Oscillation (ENSO). The analysis between the scPDSI reconstruction and large-scale atmospheric circulations during the reconstructed extreme dry and wet years can provide information about the linkages of extremes in our scPDSI record with the large-scale ocean–atmosphere–land circulation systems.

scholarly journals ANALISIS KEKERINGAN DI KABUPATEN SRAGEN DENGAN METODE PALMER, THORNTHWAITE, DAN STANDARDIZED PRECIPITATION INDEX

2021 ◽  
Vol 17 (2) ◽  
pp. 111-124
Author(s):  
Safrudin Nor Aripbilah ◽  
Heri Suprapto
Keyword(s):  
Drought Index ◽  
Southern Oscillation ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Precipitation Index ◽  
Suitable Method ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Hazard ◽  
Dry Conditions

El Nino and La Nina in Indonesia are one of the reasons that caused climate changes, which has possibility of drought and flood disasters. Sragen Regency wherethe dry season occurs, drought happened meanwhile other areas experience floods and landslides. A study on drought needs to be carried out so as to reduce the risk of losses due to the drought hazard. This study is to determine the drought index in Sragen Regency based on several methods and the correlation of each methods and its suitability to the Southern Oscillation Index (SOI) and rainfall. Drought was analyzed using several methods such as Palmer Drought Severity Index (PDSI), Thornthwaite-Matter, and Standardized Precipitation Index (SPI) then correlated with SOI to determine the most suitable method for SOI. The variables are applied in this method are rainfall, temperature, and evapotranspiration. The results showed that the drought potential of the Palmer method is only in Near Normal conditions, which is 1%, Severe drought conditions are 29% for the Thornthwaite-Matter method, and Extreme Dry conditions only reach 1,11% for the SPI method. The PDSI and SPI methods are inversely proportional to the Thornthwaite-Matter method and the most suitable method for SOI values or rainfall is the SPI method. These three methods can be identified the potential for drought with only a few variables so that they could be applied if they only have those data.Keywords: Drought, PDSI, Thornthwaite-Matter, SPI, SOI

Uncertainties in the variation of compound dry and hot events due to differences in drought indices

2021 ◽  
Author(s):  
Sifang Feng ◽  
Zengchao Hao
Keyword(s):  
Palmer Drought Severity Index ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Drought Indices ◽  
Drought Severity ◽  
Standardized Precipitation Evapotranspiration Index ◽  
The Past ◽  
Drought Indicators ◽  
The Difference ◽  
Negative Impacts

&lt;p&gt;Compound dry and hot events (CDHEs) are commonly defined as the concurrent or consecutive occurrences of the two events, which could lead to larger negative impacts than do individual extremes. The variation of CDHEs has gained increased attention in the past decades. Previous studies have detected changes in the frequency, duration, and spatial extent at regional and global scales based on observations and model simulations. However, these studies mainly focus on a single drought indicator. In the past decades, different drought indicators have been applied to characterize drought conditions, such as Standardized Precipitation Index (SPI), and Standardized Precipitation-Evapotranspiration Index (SPEI), and Palmer Drought Severity Index (PDSI). Due to the difference in these drought indicators in characterizing droughts, evaluation of CDHEs based on different drought indices may lead to a different magnitude of changes (or even opposite direction of changes). However, quantitative analysis of the uncertainties in the variation of CDHEs is still lacking. In this study, we quantitatively evaluate the uncertainties of CDHEs variations ove global areas due to differences in drought indices. Results from this study could further our understanding of changes in CDHEs under global warming.&lt;/p&gt;

Climatic influences on fire regimes in montane forests of the southern Cascades, California, USA

2008 ◽  
Vol 17 (1) ◽  
pp. 60 ◽  
Author(s):  
A. H. Taylor ◽  
V. Trouet ◽  
C. N. Skinner
Keyword(s):  
Southern Oscillation ◽  
Regional Scale ◽  
Fire Regimes ◽  
Severity Index ◽  
Drought Severity ◽  
Montane Forests ◽  
The Pacific ◽  
Response To Temperature ◽  
The Relationship ◽  
Fire Extent

The relationship between climate variability and fire extent was examined in montane and upper montane forests in the southern Cascades. Fire occurrence and extent were reconstructed for seven sites and related to measures of reconstructed climate for the period 1700 to 1900. The climate variables included the Palmer Drought Severity Index (PDSI), summer temperature (TEMP), NINO3, a measure of the El Niño–Southern Oscillation (ENSO), and the Pacific Decadal Oscillation (PDO). Fire extent at the site and regional scale was associated with dry and warm conditions in the year of the fire and regional fire extent was not associated with ENSO or PDO for the full period of analysis. The relationship between regional fire extent and climate was not stable over time. The associations of fire extent with PDSI and TEMP were only significant from ~1775 onward and the associations were strongest between 1805 and 1855. PDO and fire extent were also associated during the 1805–1855 period, and ENSO was associated with fire extent before 1800, but not after. The interannual and interdecadal variability of the fire response to temperature and drought suggests that increased periods of regional fire activity may occur when high interannual PDSI variation coincides with warm decades.

Climate effects on historical fires (1630 - 1900) in Utah

2008 ◽  
Vol 17 (1) ◽  
pp. 28 ◽  
Author(s):  
Peter M. Brown ◽  
Emily K. Heyerdahl ◽  
Stanley G. Kitchen ◽  
Marc H. Weber
Keyword(s):  
Ponderosa Pine ◽  
Southern Oscillation ◽  
Severity Index ◽  
Drought Severity ◽  
Fire Occurrence ◽  
Mixed Conifer ◽  
Climate Effects ◽  
Fire Scar ◽  
Mixed Conifer Forests ◽  
The Pacific

We inferred climate effects on fire occurrence from 1630 to 1900 for a new set of crossdated fire-scar chronologies from 18 forested sites in Utah and one site in eastern Nevada. Years with regionally synchronous fires (31 years with fire at ≥20% of sites) occurred during drier than average summers and years with no fires at any site (100 years) were wetter than average. Antecedent wet summers were associated with regional-fire years in mixed-conifer and ponderosa pine forest types, possibly by affecting fine fuel amount and continuity. NINO3 (an index of the El Niño–Southern Oscillation, ENSO) was significantly low during regional-fire years (La Niñas) and significantly high during non-fire years (El Niños). NINO3 also was high during years before regional-fire years. Although regional fire years occurred nearly twice as often as expected when NINO3 and the Pacific Decadal Oscillation were both in their cool (negative) phases, this pattern was not statistically significant. Palmer Drought Severity Index was important for fire occurrence in ponderosa pine and mixed-conifer forests across the study area but ENSO forcing was seen only in south-eastern sites. Results support findings from previous fire and climate studies, including a possible geographic pivot point in Pacific basin teleconnections at ~40°N.

scholarly journals A comparison of model simulations of Asian mega-droughts during the past millennium with proxy reconstructions

2014 ◽  
Vol 10 (3) ◽  
pp. 2685-2716 ◽  
Author(s):  
B. Fallah ◽  
U. Cubasch
Keyword(s):  
Asian Monsoon ◽  
Climate Model ◽  
Severity Index ◽  
Ice Age ◽  
Drought Severity ◽  
Model Simulations ◽  
The Past ◽  
Global Circulation Models ◽  
Proxy Reconstructions ◽  
Past Millennium

Abstract. Two PMIP3/CMIP5 climate model ensemble simulations of the past millennium have been analyzed to identify the occurrence of Asian mega-droughts. The Palmer Drought Severity Index (PDSI) is used as the key metric for the data comparison of hydro-climatological conditions. The model results are compared with the proxy data of the Monsoon Asia Drought Atlas (MADA). Our study shows that Global Circulation Models (GCMs) are capable to capture the majority of historically recorded Asian monsoon failures at the right time and with a comparable spatial distribution. The simulations indicate that ENSO-like events lead in most cases to these droughts. Both, model simulations and proxy reconstructions, point to less monsoon failures during the Little Ice Age. During historic mega-droughts of the past millennium, the monsoon convection tends to assume a preferred regime described as "break" event in Asian monsoon. This particular regime is coincident with a notable weakening in Pacific Trade winds and Somali Jet.

scholarly journals Reexamination of the Aridity Conditions in Arid Northwestern China for the Last Decade

2013 ◽  
Vol 26 (23) ◽  
pp. 9594-9602 ◽  
Author(s):  
Ke Wei ◽  
Lin Wang
Keyword(s):  
Relative Humidity ◽  
Recent Decade ◽  
Severity Index ◽  
Northwestern China ◽  
Drought Severity ◽  
Northwestern Part ◽  
Deep Soil ◽  
The Past ◽  
Arid Northwestern China ◽  
Wet Climate

Water resources are an essential part of the ecosystem in the extremely arid northwestern part of China. Previous studies revealed a dry-to-wet climate change since the late 1980s in this region, which suggested a relief from the drought condition. However, the analysis in this study using the updated data shows that the arid situation has continued and even intensified in the past decade. This is reflected by the fact that the low-level air relative humidity and deep soil relative humidity have decreased in the past decade. Examination of the standardized precipitation evapotranspiration index (SPEI) and self-calibrating Palmer drought severity index (sc-PDSI) indicates that the severity and spatial extent of aridity and drought have increased substantially in northwestern China in the most recent decade. It is shown that the drought intensification in northwestern China is mainly caused by the increase of evaporation that results from the continuous rise in temperature, which will pose a continuous threat to the ecosystem and economic development in this region, especially under the background of global warming.

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