Minimum Temperature Reconstruction Research Articles

Unprecedented recent warming as recorded by tree-ring in the western Qinling Mountains, China

Ongoing climatic warming is obvious and has significantly affected the ecosystem of the Qinling Mountains, the highest mountain region in mainland of Eastern China. Putting the progressive warming into a long-term perspective is challenging in the region due to the shortness of instrumental records. Here, we present an annual (December–November) minimum temperature reconstruction for the western Qinling Mountains from 1675 CE. The study area has experienced a continuous warming since the 1860s, and the temperature after the 1980s is unprecedented over the past three centuries. The similar variations between our reconstruction and temperature reconstructions for Asia and Northern Hemisphere indicate the close linkage between the thermal variation in the western Qinling Mountains and large-scale climate systems. Atlantic Multidecadal Oscillation (AMO) may be the primary driver influencing regional climate during the past three centuries. In addition, solar activity, strong volcanic eruption and greenhouse gas forcing have potential effects on temperature variations in the western Qinling Mountains. This study provides a long-term context for observed warming, which may have implications for warming prediction and adaptation in the western Qinling Mountains.

April–September minimum temperature reconstruction based on Sabina tibetica ring-width chronology in the central eastern Tibetan Plateau, China

Minimum temperatures have remarkable impacts on tree growth at high-elevation sites on the Tibetan Plateau, but the shortage of long-term and high-resolution paleoclimate records inhibits understanding of recent minimum temperature anomalies. In this study, a warm season (April–September) reconstruction is presented for the past 467 years (1550–2016) based on Sabina tibetica ring-width chronology on the Lianbaoyeze Mountain of the central eastern Tibetan Plateau. Eight warm periods and eight cold periods were identified. Long-term minimum temperature variations revealed a high degree of coherence with nearby reconstructions. Spatial correlations between our reconstruction and global sea surface temperatures suggest that warm season minimum temperature anomalies in the central eastern Tibetan Plateau were strongly influenced by large-scale ocean atmospheric circulations, such as the El Niño-Southern Oscillation and the Atlantic Multidecadal Oscillation.

A 250-Year Winter Minimum Temperature Reconstruction Based on Tree Rings from Luoji Mountain, Southwest China

Annually resolved temperature records spanning the past few centuries are limited in Southwest China. In this paper, we present a robust 250-year winter minimum temperature reconstruction based on the tree rings of Abies georgei Orr from Luoji Mountain, Southwest China. The tree rings exhibit significant correlations with winter minimum temperatures (Tmin) from the previous November to the current March (pNov–cMar). Based on this relationship, we reconstructed pNov-cMar Tmin from 1765 to 2014. This reconstruction accounts for 37.8% of the Tmin variance during the instrumental 1960–2014 period. Our reconstruction reveals five warm periods (1765–1785, 1795–1804, 1827–1883, 1901–1907, 1989–2014) and four cold periods (1786–1794, 1805–1826, 1884–1900, 1908–1988) over the past 250 years. Spectral analyses revealed several significant interannual (2.3–2.4a, 3.9–4.2a, 8.9–9.7a) and interdecadal (23.0–28.9a) cycles in our reconstruction series. Both spatial correlation analysis and the inter-comparison of paleoclimate records revealed that the winter Tmin reconstruction had significant positive correlations with the Atlantic Multidecadal Oscillation (AMO), with relatively consistent warm and cold periods in their variations over the past 250 years.

A 278-Year Summer Minimum Temperature Reconstruction Based on Tree-Ring Data in the Upper Reaches of Dadu River

In the context of global warming, climate change in river headwater regions and its drivers have attracted increasing attention. In this study, tree-ring width (TRW) chronology was constructed using tree-ring samples of fir (Abies faxoniana) in Dadu River Basin in the central part of the western Sichuan Plateau, China. Correlation analysis with climatic factors implies that the radial growth of trees in the region is mainly limited by temperature and has the highest correlation with the mean minimum temperature in summer (June and July) (R = 0.602, p < 0.001). On this basis, the TRW chronology was adopted to reconstruct variations in the mean minimum temperatures in summer from 1733 to 2010 in the upper reaches of Dadu River. The reconstruction equation was stable and reliable and offered a variance explanation rate of 36.2% in the observed period (1962~2010). In the past 278 years, the region experienced nine warm periods and ten cold periods. The warmest and coldest years occurred in 2010 and 1798, respectively, with values of 13.6 °C and 11.0 °C. The reconstruction was highly spatiotemporally representative and verified by temperatures reconstructed using other tree-ring data in surrounding areas. A significant warming trend was found in the last few decades. Moreover, the multi-taper method (MTM) analysis indicated significant periodic changes in quasi-2-year and 21–35-year periods, for which the El Niño Southern Oscillation (ENSO) and the Pacific decadal oscillation (PDO) could be the key controlling factors.

Spatial minimum temperature reconstruction over the last three centuries for eastern Nepal Himalaya based on tree rings of Larix griffithiana

Spatial minimum temperature reconstruction over the last three centuries for eastern Nepal Himalaya based on tree rings of Larix griffithiana

Tree-ring based minimum temperature reconstruction on the southeastern Tibetan Plateau

Increases in the annual minimum temperature (Tmin) has been more obvious than the increase in the annual mean temperature in the southeastern Tibetan Plateau (TP) over the past few decades; however, annual Tmin variability over the long-term in the southeastern TP has received scant attention. Here, we present a 413-year long tree-ring width chronology (TRW), which is composed of 22 site chronologies at high altitudes at the Hengduan Mountains on the southeastern TP. Climate–tree growth relationship analysis revealed that annual Tmin was the climatic factor that influenced radial tree growth in the area the most (R = 0.74, P < 0.001). Accordingly, we reconstructed the annual Tmin over the 1600–2012 AD period on the southeastern TP. The linear regression model between TRW chronology and annual Tmin accounted for 54.3% of the total variance in actual Tmin during the common period, 1960–2012. The close coupling of warm and cold episodes with other temperature reconstructions from surrounding regions indicated the reliability of our reconstruction. In addition, the comparison of reconstructed series with Climate Research Unit gridded data demonstrated that our reconstruction could represent the large-scale variability in annual Tmin on the TP. Furthermore, the Tmin variability exhibited similar trends with the temperature reconstructions from the TP, Asia, and northern hemisphere during the common period (1600–2012), indicating that the thermal variation in southeastern TP was consistent with the continental and hemispheric scale climate system variabilities. Atlantic Multi-Decadal Oscillation (AMO) and solar activity were observed to be key factors influencing annual Tmin variation over the southeastern TP. The results of the moving correlation analyses implied that the radial forest growth at high altitudes on the southeastern TP remained consistent with regional Tmin variation, and the decrease in precipitation has not yet limited forest growth.

Tree ring width‐based January–March mean minimum temperature reconstruction from Larix gmelinii in the Greater Khingan Mountains, China since AD 1765

AbstractA ring‐width chronology of Larix gmelinii (LG) was developed in the northern Greater Khingan Mountains region of China. The response function analyses revealed that the local mean minimum temperature of January–March (T1–3) was the most limiting factor affecting the radial growth of LG trees. Based on correlation analysis, a reconstructed T1–3 series from 1765 to 2013 was produced using standard ring‐width chronology. The reconstruction explained 41.2% of the total variance in recorded monthly mean minimum temperatures from 1960 to 2013. The reconstructed T1–3 series had similar variability when compared with the May–September mean temperature reconstruction in Inner Mongolia (IM) and the February–March mean minimum temperature reconstruction in Yichun (YC). This reconstructed T1–3 series also captured the severe snow disaster and cold wave events recorded from historical documents in Heilongjiang and Inner Mongolia. Spatial correlations between reconstructed series and gridded temperature data also provided a high level of confidence. In addition, significant relationships between the reconstructed T1–3 series and the Pacific Decadal Oscillation (PDO), El Niño–Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), solar activity, indicated that the T1–3 variation might be influenced by large‐scale ocean–atmosphere interactions.

Tree ring–based minimum temperature reconstruction in the central Hengduan Mountains, China

We developed a tree ring-width chronology of Abies georgei at the timber line in the Big Snow Mountain Scenic Area in northwestern Yunnan, China. The climate-tree growth response analysis indicated that temperature was the predominant regulator of A. georgei growth in this region. An annual mean minimum temperature (AMMT) reconstruction spanning A.D. 1837–2016 was developed with a linear regression model (y = 1.0x − 6e − 5) that accounted for 50.7% of the actual temperature variance during the common period (1960–2016). Based on the reconstructed temperature series, the warmer periods were 1840–1845, 1855–1865, 1880–1895, 1945–1965, and from 1995 until the present day, and the cold periods were 1870–1880, 1900–1930, and 1966–1980. By comparing our results with other regional tree ring records from surrounding areas, a distinctive amount of common warm and cold periods were found, indicating the reliability of our temperature reconstruction and suggesting that the climate in the study area was part of a large-scale climate system.

A 333-year record of the mean minimum temperature reconstruction in the Western Tianshan Mountains, China

In this paper, a fragile ecological area in the Western Tianshan National Nature Reserve of China was selected as the research region, and &lt;i&gt;Picea schrenkiana&lt;/i&gt;, which is sensitive to climate change, was selected as the research object. The mean minimum temperature in the growing season of the previous year (May to September) was the main limiting factor for tree radial growth based on an analysis of the relationship between chronological series and climatic factors during 1959–2012 (&lt;i&gt;r&lt;/i&gt; = –0.792, &lt;i&gt;p&lt;/i&gt; &lt; 0.05). Moreover, the relationship was stable, which showed that tree rings can be used as alternative materials for climate reconstruction. Therefore, the mean minimum temperature of the previous year in 1680–2012 was reconstructed, and the explained variance of the reconstruction equation was 62.7% (&lt;i&gt;R2adj&lt;/i&gt; = 62.0%, F = 85.8). The 31 dramatically altered years were found via characteristic year analyses, and extreme changes occurred most often under relatively warm conditions. The mean minimum temperature in the reconstruction shows a clear warming trend by the 11-year moving average of the reconstructive series since the 1950s (the temperature increase: 0.341°C/decade). The driving factors of the mean minimum temperature were influenced mainly by the interaction of solar activity and large-scale atmospheric–oceanic variability, especially the westerly circulations.

A tree-ring–based summer (June–July) minimum temperature reconstruction for the western Kunlun Mountains since AD 1681

Knowledge of past climatic variability for the Tibetan Plateau (TP), especially the northwestern part of it, is still limited due to the lack of long-term meteorological records. Within this study, we developed a summer (June–July) minimum temperature reconstruction since 1681 based on annual tree-ring width of Schrenk’s spruce (Picea schrenkiana Fisch. et Mey.) from a humid timberline on the western Kunlun Mountains. Our reconstruction passed the statistical calibration and validation tests, and accounted for 37.69% of the variance for the instrumental record during the period 1960–1996. The reconstruction mainly exhibited annual to decadal temperature variability, with cold periods in 1694–1696, 1745–1749, 1823–1824, and 1915–1921, and warm periods in 1755–1760, 1795–1799, and 1894–1896. Spatial correlations and comparisons with the Asia summer temperature reconstructions further verified our temperature reconstruction and its capability to serve as a proxy for large-scale temperature variability on the northwestern TP. Our results clearly indicate the great potential to perform dendrochronological studies on the western Kunlun Mountains.

Summer temperature variability inferred from tree-ring records in the central Hengduan Mountains, southeastern Tibetan Plateau

Current understanding of the paleoclimatic variability across the Tibetan Plateau (TP) is still limited because of the lack of long-term climatic records. We developed a regional tree–ring width chronology of Picea likiangensis var. balfouriana from the central Hengduan Mountains region, in the southeastern TP. Climate-growth correlation analysis revealed that the current year’s July (cJuly) and the current year’s August (cAugust) mean minimum temperature was the main climatic factor controlling tree-ring growth. Using a linear regression function, we reconstructed this indicator for the past 214 years (1795–2008) to produce the first mean minimum temperature reconstruction for the central Hengduan Mountains. The reconstruction satisfied all statistical calibration and validation tests, and represented 35.9% of the temperature variance recorded over the 1958–2008 instrumental period (34.6% after adjusting for the loss of the degrees of freedom). During the past 214 years, two major cold periods were identified from 1839 to 1853 and 1857–1942, and four major warm periods from 1802 to 1813, 1819–1838, 1972–1981, and 1988–2008. The degree of warming from 1988 to 2008 was unprecedented over the past two centuries. Spatial field correlation with the gridded temperature dataset revealed that our reconstruction captures large-scale regional temperature variations for the southeastern TP and its vicinity. The reconstructed variations were consistent when compared to other regional temperature datasets, historical documents, and records of glacier fluctuations in the surrounding high mountains. This consistency with multiple records suggests that our reconstructed sequence is reliable and it could represent historical large-scale temperature changes on the southeastern TP.

May–July mean minimum temperature variability in the mid-Qinling Mountains, central China, since 1814 CE

A tree-ring width (TRW) chronology was developed from Larix chinensis Beissn at the divide sampling site in the mid-Qinling Mountains, central China. The relationships between tree radial growth and climate factors on several timescales (Daily, Pentad, Dekad and Month) were studied. Compared to precipitation, temperature shown stronger impacts on Larix chinensis Beissn on each timescales. Particularly, pentad was a more suitable scale for tree growth-climate response analysis. Significantly positive correlation was found between tree-ring index and the mean minimum temperature from May to July, i.e. 28 to 42 pentads (r = 0.625, p < 0.001). Based on this relationship, the May to July mean minimum temperature was reconstructed in the last 194 years, with an explained variance of 39.1% for the calibration period from 1957 to 2007. The results of leave-one-out tests showed that the reconstruction mode was stable and reliable. This minimum temperature reconstruction revealed that cold spans mainly occurred in 1816–1831, 1840–1852, 1879–1888 and 1976–1984, while warm spans prevailed in 1863–1878, 1889–1897, 1916–1932 and 2000–2007. Comparisons with other surrounding temperature series from tree rings, our reconstruction could provide a good regional representation of temperature change in the mid-Qinling Mountains. The reconstructed minimum temperature series was further verified by dryness-wetness index (DWI) sequence based on Chinese historical literature. Significant quasi-periodic signals at 32.2a, 20.5a, 8.9–13.1a and 2-8a suggested that temperature variability in the study area may associate with the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO).

A 564-year annual minimum temperature reconstruction for the east central Tibetan Plateau from tree rings

Minimum temperatures have increased rapidly on the Tibetan Plateau (TP) in recent decades, but there is still a lack of long-term background information to evaluate the nature of the anomaly. Here we present a 709-year tree-ring width chronology from Sabina tibetica Kom. on the east central TP, with reliable coverage from 1451 to 2014. Based on the significant relationship between tree growth and annual minimum temperature (Tmin), from previous April to current March, we reconstruct the pApril-cMarch Tmin for the past 564years. The reconstruction shows six major warm (1490–1623, 1713–1729, 1784–1812, 1868–1877, 1918–1954, 1989–2014) and six major cold (1451–1489, 1624–1712, 1730–1783, 1813–1853, 1878–1917, 1955–1988) periods during the past five hundred years. The level of warming from 1989 to 2014 is unprecedented over the past five centuries. Comparison with other minimum temperature records indicates that our Tmin reconstruction represents large-scale temperature changes on the eastern TP. The positive correlation between the Tmin reconstruction and the Atlantic Multidecadal Oscillation (AMO) suggests that the latter may have played a crucial role on multidecadal temperature variations over the east central TP, with high temperatures coincident with the warm phases of the AMO, and low temperatures related to the cold phases of the AMO, respectively.

A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China

Abstract. A ring-width series was used as a proxy to reconstruct the past 414-year record of April–July minimum temperature at Laobai Mountain, northeast China. The chronology was built using standard tree-ring procedures for providing comparable information in this area while preserving low-frequency signals. By analyzing the relationship between the tree-ring chronology of Korean pine (Pinus koraiensis) and meteorological data, we found that the standard chronology was significantly correlated with the April–July minimum temperature (r = 0.757, p &lt; 0.01). Therefore, the April–July minimum temperature since 1600 (more than six trees, but the expressed population signal (EPS) is greater than 0.85 since 1660) was reconstructed by this tree-ring series. The reconstruction equation accounted for 57.3 % of temperature variation, and it was proved reliable by testing with several methods (e.g., sign test, product mean test, reduction of the error, and coefficient of efficiency). Reconstructed April–July minimum temperature on Laobai Mountain showed six major cold periods (1605–1616, 1645–1677, 1684–1691, 1911–1924, 1930–1942, and 1951–1969) and seven major warm periods (1767–1785, 1787–1793, 1795–1807, 1819–1826, 1838–1848, 1856–1873, and 1991–2008) during the past 414 years. The reconstructed low-temperature periods in the 17th and early 18th century were consistent with the Little Ice Age (LIA) in the Northern Hemisphere, and the rate of warming in the 19th century was significantly slower than that in the late 20th century. In addition, the reconstructed series was fairly consistent with the historical and natural disaster records of extreme climate events (e.g., cold damage and frost disaster) in this area. This temperature record provides new evidence of past climate variability, and can be used to predict the climate trend in the future in northeast China.

Recent warming evidence inferred from a tree-ring-based winter-half year minimum temperature reconstruction in northwestern Yichang, South Central China, and its relation to the large-scale circulation anomalies.

High-resolution winter temperature reconstructions in China are rare, yet vital for the comprehensive understanding of past climate change. In the present work, the first winter-half year minimum mean temperature from previous November to current April in northwestern Yichang, South Central China, was reconstructed back to 1875 based on tree-ring material. The reconstruction can explain 55% of the variance over the calibration period during 1955-2011. The temperature maintained at comparatively low level before 1958, and an abnormal warming was seen since 1959. However, the warming trend stagnated after 2000AD. 2001-2010 was the warmest decade not only during the instrumental period but also during the whole reconstructed period. The reconstruction indicates good spatial resemblance to other temperatures series in adjacent areas and Northern Hemisphere, yet the recent warming in this study is earlier and more prominent than that of Southeast China. This work also manifests that the winter-half year minimum temperature in study area has good agreement with summer (June-September) maximum temperature variation in Southeast China at decadal scale, except that the winter-half year warming in recent decades is more evident than summer. This reconstruction is not only useful in improving our knowledge of long-term temperature variation but also useful in predicting the tree growth dynamics in the future in the study area.

Tree-ring based summer minimum temperature reconstruction for the southern edge of the Qinghai-Tibetan Plateau, China

Information about historical summer temperature variability is rare on the Qinghai- Tibetan Plateau (QTP). Here we report a 290 yr summer (June to August) mean minimum tem - perature (SMMT) record reconstructed from tree-ring widths of alpine juniper Sabina squamata in Yadong County at the southern edge of QTP, China. The reconstruction accounts for 51.2% of the SMMT variance in the instrumental period from 1956 to 2002. Five cold intervals in 1725�1734, 1745�1789, 1817�1825, 1860�1869 and 1967�1978, and 4 warm intervals in 1735� 1744, 1790�1816, 1870�1879 and 1990�2002 were identified. Wavelet analysis of the recon- structed temperatures suggested the existence of 2 to 7 yr cycles in discontinuous periods and 20 to 25 yr cycles in the 1850s to 1880s. The reconstructed summer temperature variations were consistent with other temperature records from tree rings, ice cores and glacier activities on the QTP, which demonstrate the fidelity of the reconstruction and suggested that the climate in the study region was part of a large-scale climate system. The 1980s to 2000s were the warmest period in the last 3 centuries in our tree-ring records, but the amplitude of the warming was still within the natural variation.

Reconstructed temperature for Yong'an, Fujian, Southeast China: Linkages to the Pacific Ocean climate variability

Variations in ring width of Pinus massoniana were used to develop high-resolution climate proxy data to extend the existing climate record in Yong'an, Fujian Province, Southeast China. Growth–climate response analyses showed that the total ring width (TRW) in the subtropical zone of Fujian Province is mainly influenced by summer–autumn temperature variability. Based on the total ring width chronology derived from one chronology site (LBY), we developed July–October minimum temperature reconstruction for the period A.D. 1803–2008. The climate/tree-growth model accounts for 42.2% of the instrumental temperature variance during the period 1954–2008. Warm periods occurred during 1808–1815, 1833–1853, 1862–1871, 1895–1906, 1914–1927 and 1973–present; while the periods of 1803–1807, 1816–1832, 1854–1861, 1872–1894, 1907–1913 and 1928–1972 were relatively cold. There is a reasonable agreement with the cold and warcum periods previously estimated from tree-rings around Western Pacific Ocean. The climate correlation analyses with summer APO and gridded climate dataset revealed that our season temperature reconstruction contains the strong climate signals for Asian-Pacific.