Tree-Ring-Based Drought Reconstruction in Northern North China over the Past Century

Abstract

A tree-ring width chronology was developed from the Chinese pine (Pinus tabuliformis) in northern North China. To acquire a long-term perspective on the history of droughts in this region, the Standardized Precipitation Evapotranspiration Index (SPEI) from August of the previous year to February of the current year was reconstructed for the period of 1903–2012 AD. The reconstruction explained 46.6% of the instrumental records over the calibration period of 1952–2012. Five dry periods (1916–1927, 1962–1973, 1978–1991, 1994–1999 and 2002–2005) and three wet periods (1908–1915, 1928–1961 and 1974–1977) were found in the reconstructed period, and most of the dry years (periods) in the reconstruction were supported by historical records. Comparisons between the reconstruction and other nearby dryness/wetness indices and precipitation reconstructions demonstrated a good repeatability and high reliability in our reconstruction. Spatial correlation implied that the reconstruction could represent regional hydroclimatic characteristics on a larger regional scale. Significant periodicities and correlations were observed between the reconstructed data and the quasi-biennial oscillation (QBO), El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), which suggested that the hydroclimatic variation in northern North China may be closely connected to remote oceans. The significant and high correlation between the reconstructed series and sea surface temperatures (SSTs) in the eastern equatorial and Southeast Pacific Ocean indicated that ENSO may be the main factor influencing the regional climate.

Reconstruction of July-September standardized precipitation-evapotranspiration index (SPEI) for the Hindu Kush region of Northern Pakistan

“…The correlation between the standard chronology of C. deodara and drought during July-September, which extends from June of the previous year to September of the current year (figure 4), is consistent with previous studies on other conifer species in the Hindu Kush-Himalaya region of Pakistan [27,32,36]. Studies on the Tibetan Plateau (TP) in China [50][51][52][53] and the central Himalaya [54,55] have also reported that the forest growth of conifers is sensitive to drought.…”

Local Topography Has Significant Impact on Dendroclimatic Response of Picea jezoensis and Determines Variation of Factors Limiting Its Radial Growth in the Southern Sikhote-Alin

“…Therefore, the negative correlation between July SPEI values and tree-ring chronologies, as observed with precipitation, reflects the negative impact of overmoistening on the radial growth of Jezo spruce. This is an interesting result because SPEI is usually used as a drought index, not for overmoistening [83][84][85]. Despite precipitation being highest in August, the SPEI index reaches its highest positive values in July.…”