A chironomid-based mean July temperature inference model from the south-east margin of the Tibetan Plateau, China

Abstract

Abstract.A chironomid-based calibration training set comprised of 100 lakes from south-western China was established. Multivariate ordination analyses were used to investigate the relationship between the distribution and abundance of chironomid species and 18 environmental variables from these lakes. Canonical correspondence analyses (CCAs) and partial CCAs showed that mean July temperature is one of the independent and significant variables explaining the second-largest amount of variance after potassium ions (K + ) in 100 south-western Chinese lakes. Quantitative transfer functions were created using the chironomid assemblages for this calibration data set. The second component of the weighted-average partial least squares (WA-PLS) model produced a coefficient of determination (r 2 bootstrap ) of 0.63, maximum bias (bootstrap) of 5.16 and root-mean-square error of prediction (RMSEP) of 2.31 • C. We applied the transfer functions to a 150-year chironomid record from Tiancai Lake (26 • 38 3.8 N, 99 • 43 E; 3898 m a.s.l.), Yunnan, China, to obtain mean July temperature inferences. We validated these results by applying several reconstruction diagnostics and comparing them to a 50-year instrumental record from the nearest weather station (26 • 51 29.22 N, 100 • 14 2.34 E; 2390 m a.s.l.). The transfer function performs well in this comparison. We argue that this 100-lake large training set is suitable for reconstruction work despite the low explanatory power of mean July temperature because it contains a complete range of modern temperature and environmental data for the chironomid taxa observed and is therefore robust.

Summer temperature variability inferred from subfossil chironomid assemblages from the south-east margin of the Qinghai–Tibetan Plateau for the last 5000 years

“…Transfer functions based on the subfossil chironomid species assemblages have been developed from many different regions and most are used for palaeo-temperature reconstructions (Chang et al, 2015a, 2015b; Heiri et al, 2011, 2014; Larocque et al, 2001; Lotter et al, 1999; Woodward and Shulmeister, 2006). Recently, a chironomid-based mean July temperature transfer function was established using 100 lakes from south-western China (Zhang et al, 2016a). This transfer function has already been applied to a short record, and the results suggest that robust reconstructions can be obtained from high-altitude regions of Yunnan (Zhang et al, 2016a).…”

A quantitative temperature reconstruction of the ‘Little Ice Age’ in southern China

“…2.4°C) was only marginally higher than other proxies. For instance, chironomid-based transfer functions usually have a RMSEP within 2°C (Heiri et al, 2011; Zhang et al, 2017). The maximum magnitude of mean annual temperature fluctuations over the past millennium is within ca.…”

Review and test of reproducibility of subdecadal resolution palaeoenvironmental reconstructions from microfossil assemblages

“…The Nurmijärvi paper reports that there is a 4-8 year lag (perhaps caused by the ecological and taphonomic processes described above) in the chironomid response to temperature, which would seem to preclude the development of a good calibration-in-time model. Zhang et al (2017a) report that they correlate their July air temperature reconstruction with a three-year moving average of the instrumental data (Zhang et al, 2017b). However, the instrumental time series has been mis-processed.…”

“…Chrysophyte stomatocysts have also been used to reconstruct summer calcium concentrations (Hernández-Almeida et al, 2015b), which might reflect summer mixing and so were correlated with summer wind. High-resolution chironomid head capsule stratigraphies have been used to reconstruct summer air (e.g., Larocque et al, 2009a;Luoto and Ojala, 2016;Zhang et al, 2017a) and water (Medeiros et al, 2012) temperature. Highresolution pollen records have been used to reconstruct summer air temperature (Kamenik et al, 2009).…”