Summer Temperature Changes Research Articles

Study of the Future Evolution of the Urban Climate of Paris by Statistical–Dynamical Downscaling of the EURO-CORDEX Ensemble

Abstract High-resolution urban climate projections are needed for local decision-making on climate change adaptation. Regional climate models have resolutions that are too coarse to simulate the urban climate at such resolutions. A novel statistical–dynamical downscaling (SDD) approach is used here to downscale the EURO-CORDEX ensemble to a resolution of 1 km while adding the effect of the city of Paris (France) on air temperature. The downscaled atmospheric fields are then used to drive the Town Energy Balance urban canopy model to produce high-resolution temperature maps over the period 1970–2099, while maintaining the city’s land cover in its present state. The different steps of the SDD are evaluated for the summer season. The regional climate models simulate minimum (maximum) temperatures (TN/TX) that are too high (low). After correction and downscaling, the urban simulations inherit some of these biases but give satisfactory results for summer urban heat islands (UHIs), with average biases of −0.6 K at night and +0.3 K during the day. Changes in future summer temperatures are then studied for two greenhouse gas emission scenarios, RCP4.5 and RCP8.5. Outside the city, the simulations project average increases of 4.1 and 4.8 K for TN and TX for RCP8.5, respectively. In the city, warming is lower, resulting in a decrease in UHIs of −0.19 K at night (from 2.1 to 1.9 K) and −0.16 K during the day. The changes in UHIs are explained by higher rates of warming in rural temperatures due to lower summer precipitation and soil water content and are partially offset by increased ground heat storage in the city.

The LGM termination in the southeastern Tibetan plateau: View from high-frequency LGM glacier fluctuations in the Boshula mountain range

Climate processes that operated during the end of the Last Glacial Maximum (LGM) are remarkable for its global synchroneity. Atmospheric CO2 concentrations have been widely seen as its cause. However, the stepwise LGM deglaciation of mountain glaciers in both hemispheres complicates this view, and signifies additional factors that likely prompted the onset of LGM termination. Here, we examine LGM climate change in the Hengduan Mountains (HDM), southeastern Tibetan Plateau (TP), based on 10Be surface exposure dating of moraine boulders (n = 51). The timing of four moraine-building events is constrained to 22.8 ± 1.0 ka, 21.2 ± 0.6 ka, 20.4 ± 0.6 ka, and 19.2 ± 0.6 ka. These precisely-dated events provide convincing evidence of millennial-to centennial-scale glacial activities in the TP during the LGM. We show that these high-frequency glacier fluctuations likely reacted to a combination of changes in regional summer temperature related to sea surface temperatures as well as monsoon precipitation. The pronounced glacial retreat is dated at 19.2 ± 0.6 ka, representing the end of the LGM in the HDM. That is, the onset of LGM termination preceded the rapid CO2 rise at ∼18 ka. We suggest that the LGM termination in the southeastern TP was initiated by ice-sheet shrinkage, which induced changes in summer temperature and monsoon precipitation via ocean-atmosphere interactions.

Tree-Ring Chronologies from the Upper Treeline in the Russian Altai Mountains Reveal Strong and Stable Summer Temperature Signals

Radial tree growth at high-elevation and high-latitude sites is predominantly controlled by changes in summer temperature. This relationship is, however, expected to weaken under projected global warming, which questions the reliability of tree-ring chronologies for climate reconstructions. Here, we examined the growth–climate response patterns of five tree-ring width (TRW) and maximum latewood density (MXD) chronologies of larch (Larix sibirica) from upper-treeline ecotones in the Altai Mountains, which is a key region for developing millennial-long dendroclimatic records in inner Eurasia. The TRW and MXD chronologies exhibited significant year-to-year coherency within and between the two parameters (p < 0.001). While TRW is mostly influenced by temperature changes during the first half of the growing season from June to July (r = 0.66), MXD is most strongly correlated with May–August temperatures (r = 0.73). All seasonal temperature signals are statistically significant at the 99% confidence level, temporally stable back to 1940 CE, the period with reliable instrumental measurements, and spatially representative for a vast area of inner Eurasia between northeastern Kazakhstan in the west, northern Mongolia in the east, southern Russia in the north and northwestern China in the south. Our findings demonstrate the paleoclimatic potential of TRW and especially MXD chronologies and reject any sign of the ´divergence problem´ at these high-elevation, mid-latitude larch sites.

Constraining future surface air temperature change on the Tibetan Plateau

Abstract The rapid warming of the Tibetan Plateau (TP) in recent decades has led to severe consequences, including the melting of glaciers and snow cover, which further accelerates warming. Accurately projecting the magnitude of future warming is crucial for effective climate change adaptation. However, the projection of future temperature change is model dependent. In this study, we demonstrate a significant correlation between the historical intermodel warming trend and future temperature change, suggesting this relationship could be used to calibrate the best estimate of projections and reduce the uncertainty by observations. For a high emission scenario, the constraint helps to narrow down the uncertainty range of annual and summer temperature change on the western TP by up to 2 °C and 4 °C, respectively, in the end of this century. The most substantial calibrated increase of future change is in winter up to 2 °C, followed by autumn with an increase of up to about 1 °C. Discrepancies of historical warming trend among different observation datasets expose the largest impact on the constrained best estimate compared with emergent relationship derived from different climate models and historical periods.

Incorporating projected climate conditions to map future riparian refugia

AbstractIdentifying areas expected to remain buffered from climate change and maintain biodiversity and ecological function (i.e., climate refugia) is important for climate adaptation planning. As structurally diverse transitional zones between terrestrial and aquatic environments, riparian areas are often biological hotspots and provide critical corridors for species movement, particularly in arid and semi‐arid regions. In our study region in the western and central USA, identifying riparian areas that could serve as climate refugia is a priority for wildlife managers. We mapped areas with connected riparian habitats that, based on landscape diversity and projected changes in summer temperatures and landscape runoff, are expected to serve as climate refugia. To incorporate uncertainty and balance the need for near‐ and long‐term planning, we mapped potential refugia for 2 future time periods (2040–2069, 2070–2099) based on 2 climate models that represented divergent but plausible climate outcomes. The approach we developed is not constrained by physiology or behavior of target species and can be used to identify areas expected to fare comparatively well under a wide range of future climate scenarios. Our approach can also be used to identify areas where restoration could increase riparian connectedness and climate resilience.

Pollen-based seasonal temperature reconstruction in Northeast China over the past 10,000 years, and its implications for understanding the Holocene Temperature Conundrum

The Holocene Temperature Conundrum refers to the mismatch between proxy-based temperature records and those based on climate model simulations. A possible reason for this mismatch is a putative proxy-based bias in reconstructed summer temperatures, and therefore, regional reconstructions of seasonal temperature are crucial for resolving the conundrum. In this paper, we reconstruct vegetation and climate changes over the last ∼10,000 years BP based on a high-resolution pollen record from Gushantun peatland, Changbai Mountains, Northeast China. Multiple quantitative reconstruction approaches were used and weighted averaging partial least squares regression (WAPLS) was found to be the most appropriate method for reconstructing Holocene temperature and precipitation. The reconstructed climate record shows that the Holocene Climate Optimum occurred between 8 ka and 6 ka and exhibited a cold month mean temperature that was 3 °C warmer than modern temperatures. Climate gradually cooled during late Holocene with a minimum cold month temperature of −19.6 °C. Four prominent cold events occurred around 8.7 ka BP, 7.8 ka BP, 5.7 ka BP, and 2.5 ka BP with an amplitude variation up to 3 °C. The synthesized seasonal temperature time series and a comparison with other proxies show that the decreasing trend in mean annual temperature is not a seasonal bias caused by summer temperature change. This study provides evidence of a Holocene seasonal temperature change at a regional scale and insights for further understanding of the Holocene Temperature Conundrum.

Local summer temperature changes over the past 440 ka revealed by the total air content in the Antarctic EPICA Dome C ice core

Abstract. Seasonal temperature reconstructions from ice cores are missing over glacial–interglacial timescales, preventing a good understanding of the driving factors of Antarctic past climate changes. Here the total air content (TAC) record from the Antarctic EPICA Dome C (EDC) ice core is analyzed over the last 440 ka (thousand years). While the water isotopic record, a tracer for annual mean surface temperature, exhibits a dominant ∼100 kyr cyclicity, the TAC record is associated with a dominant ∼40 kyr cyclicity. Our results show that the TAC record is anti-correlated with the mean insolation over the local astronomical summer half-year. They also show for the first time that it is highly anti-correlated with local summer temperature simulated with an Earth system model of intermediate complexity. We propose that (1) the local summer insolation controls the local summer temperature; (2) the latter, through the development of temperature gradients at the near-surface of the ice sheet (<2 m), is affecting the surface snow structure; and (3) those snow structure changes propagating down to the bottom of the firn through densification are eventually controlling the pore volume at the bubble close-off and consequently the TAC. Hence, our results suggest that the EDC TAC record could be used as a proxy for local summer temperature changes. Also, our new simulations show that the mean insolation over the local astronomical summer half-year is the primary driver of Antarctic summer surface temperature variations, while changes in atmospheric greenhouse gas (GHG) concentrations and Northern Hemisphere (NH) ice sheet configurations play a more important role in Antarctic annual surface temperature changes.

Rising summer river water temperature across Canada: spatial patterns and hydroclimatic controls

Understanding the spatio-temporal variability of climate-induced river water temperature change is critical for identifying hotspots and assessing the impacts on ecological and socioeconomic systems. Here, we employ the air2stream model reconstructed river temperature records for 106 stations in Canada (Nash Sutcliffe coefficient goodness-of-fit: minimum = 0.79; median = 0.93; maximum = 0.97) to analyze summer temperature changes over the years 1980–2018. Results reveal widespread river temperature increases from June to September, with significantly increasing trends for about 40%–60% of stations. Additionally, we find significantly rising 7-day maximum temperature and increasing occurrences over the critical 18 and 20 °C thresholds for about 30%–65% of stations. Furthermore, by employing the Ward’s agglomerative hierarchical clustering machine learning (ML) method, we identify eight regions of spatially coherent variability and change. We find that the south-east, coast and northern prairies are the regions of high vulnerability because of the likely impacts of rising summer water temperatures on cold-water aquatic species. Additionally, by using the random forests ML method, we demonstrate that mean air temperature and its trends are the primary drivers of mean water temperature and trends, respectively. Thus, with the projected enhanced air temperature increase across Canada, an amplified future summer river warming can be expected, which could have severe consequences, particularly in already thermally-stressed river systems.

Two chironomid-inferred mean July air temperature reconstructions in the South Carpathian Mountains over the last 2000 years

We present chironomid-based reconstructions of mean July air temperature changes over the last 2000 years from Lake Latoriței (1530 m a.s.l.) in the Southern Carpathians. A multi-proxy analysis was performed along a 58 cm long sediment core and two training sets were used for quantitative July air temperature reconstructions: the Eastern-European (EE, 212 lakes) and the Finnish-Polish-Carpathian (FPC, 273 lakes). The transfer functions had a coefficient of determination ( r2) 0.88 and 0.91 with a root mean squared error of prediction (RMSEP) 0.88°C and 1.02°C. Despite possible biases resulting from methodological problems and the ecological complexity of the chironomid response to both climatic and environmental changes, the agreement of the temperature reconstruction of Lake Latoriței with other alpine records suggests that the transfer function successfully reconstructed past summer temperatures between 750 and 1830 CE. Biases in the temperature reconstruction in the period before 750 and after 1830 CE were likely caused by increased abundance of rheophilic and semi-terrestrial chironomid species related to increased inflow activity before 750 CE and local land use changes after 1830 CE, which was also indicated by increasing deforestation and increasing lake productivity in the pollen and diatom records. Our results suggest that the region experienced a warm period between 750 and 1360 CE, and a cold period between 1360 and 1600 CE followed by fluctuating summer temperatures until 1830 CE. These events were associated with the so-called ‘Mediaeval Warm Period’ (MWP) and the ‘Little Ice Age’ (LIA), respectively. The inference models reconstructed a decrease in July air temperatures by 0.7°C–1.1°C during the LIA relative to the warmer MWP. We also demonstrated that the FPC training set gives better results, supporting that local/continental training sets are efficient to detect weak amplitude summer temperature changes in the Late-Holocene.

What Aspect of Model Performance is the Most Relevant to Skillful Future Projection on a Regional Scale?

Abstract Weighting models according to their performance has been used to produce multimodel climate change projections. But the added value of model weighting for future projection is not always examined. Here we apply an imperfect model framework to evaluate the added value of model weighting in projecting summer temperature changes over China. Members of large-ensemble simulations by three climate models of different climate sensitivities are used as pseudo-observations for the past and the future. Performance of the models participating in the phase 6 of the Coupled Model Intercomparison Project (CMIP6) are evaluated against the pseudo-observations based on simulated historical climatology and trends in global, regional, and local temperatures to determine the model weights for future projection. The weighted projections are then compared with the pseudo-observations in the future period. We find that regional trend as a metric of model performance yields generally better skill for future projection, while past climatology as performance metric does not lead to a significant improvement to projection. Trend at the grid-box scale is also not a good performance indicator as small-scale trend is highly uncertain. For the model weighting to be effective, the metric for evaluating the model’s performance must be relatable to future changes, with the response signal separable from internal variability. Projected summer warming based on model weighting is similar to that of unweighted projection but the 5th–95th-percentile uncertainty range of the weighted projection is 38% smaller with the reduction mainly in the upper bound, with the largest reduction appearing in southeast China.

CLIMATIC FACTORS CHARACTERIZING THE MOISTURE SUPPLY OF THE TERRITORY AND THEIR EFFECT ON THE QUALITY INDICATORS OF GRAPES

The study of scientific problem, to which this research is devoted, is due to planetary climate change, manifested in an increase in the average annual air temperature, rapid changes in winter and summer temperatures, and a lack of precipitation.
 For today, there is a serious problem of adapting plants to climate change due to an increase in water deficiency in many regions of the world. Climate change creates significant uncertainty in the potential adaptability of grape plants, as well as in the prospects for viticulture development in general.
 The study and generalization of territorial distribution of climatic factors that characterize a particular region, as well as their effect on the quality characteristics of raw materials and finished products, are attractive from the point of better understanding and forecasting the potential impact on agricultural systems. The obtained data consumption will allow improving the forecast of climate change consequences in the medium term, and in relation to particular terroirs.
 The goal is to study the effect of climatic factors that characterize the moisture supply of the territory on the quality indicators of grapes.
 Materials and methods. The objects of the study were grapes of white and red cultivars, different in agroecological aspect, and growing in micro regions of Crimea. To identify the effect of factors characterizing the moisture supply of the territory on the quality indicators of raw materials for winemaking products, the amount of precipitation from the beginning of growing season to the harvesting, the amount of precipitation for the last month before harvest, and hydrothermal coefficient of Selyaninov were selected. The assessment of grapes was carried out according to the indicators of carbohydrate-acid complex (mass concentration of sugars, titratable acids, pH value, profile of organic acids), as well as the glucoacidimetric indicator revealing the degree of grape ripeness.
 Results and conclusion. Climatic factors characterizing the moisture supply of viticultural and winemaking regions of Crimea were assessed. The studies carried out made it possible to reveal variations in the concentration of carbohydrate-acid complex components depending on the changing ability of environmental factors. A significant precipitation deficiency was observed on the Peninsula. According to the value of hydrothermal coefficient of Selyaninov (did not exceed 1), most of the territory was classified as an arid or very arid zone. A correlation between the hydrothermal coefficient and mass concentration of grape sugars (r=-0.63) was established for red grapevine cultivars. The data obtained indicate that an increase in the amount of precipitation during growing season contributes to a moderation of sugar accumulation in grapes. Similar pattern was not established for white grapevine cultivars. There was a direct correlation of the mass concentration of malic acid on the amount of precipitation in the last month before harvest (r=0.78).

Reconstructions of Little Ice Age glaciers and climate in the Tanggula Mountains, Central Tibet Plateau

Mountain glaciers are one of the most sensitive indicators of climate change. Reconstructing past glacier extents provides valuable insights into the climate change for specific regions where instrumental records are not enough and even absent. In the paper we mapped the outlines for 691 Little Ice Age (LIA) glaciers in terms of prominent moraines beyond contemporary glaciers in the Tanggula Mountains, central Tibetan Plateau (TP). Based on these glacier outlines, we reconstructed the ice thicknesses and surfaces for the LIA glaciers in the region. Accordingly, we calculated the equilibrium-line altitudes (ELAs) for contemporary and LIA glaciers. By comparing the ELAs between the contemporary and LIA glaciers, we estimated the LIA summer temperature decreases in different subregions of the Tanggula Mountains. Since the LIA, the ELA have risen by 35.6 ± 18.8 m, 26.1 ± 17.6 m, and 63.1 ± 38.6 m in the respective western, central, and eastern subregions of the Tanggula Mountains. Assuming no change in precipitation, the LIA summer temperature would decrease by 0.22 ± 0.12 °C, 0.14 ± 0.09 °C, and 0.34 ± 0.21 °C in the three subregions, respectively. Moreover, glaciers in the western, central, and eastern subregions have lost 13.3%, 23.9%, and 42.8% of their area, 15.4%, 25.3%, and 39.6% of their length, and 20.8%, 39.0%, and 61.0% of their volume, respectively. By compiling the LIA ELA data from previous studies, we also estimated the LIA summer temperature changes for other regions of the TP. The LIA ELA and summer temperature changes relative to the present showed a decreasing trend from the edges towards the interior on the TP.

Reconstruction of temperature and monsoon precipitation in southwestern China since the last deglaciation

Monsoon precipitation and temperature are the crucial components of the Indian monsoon climate, yet their spatial-temporal relationship remains unclear. In this study, we reconstruct the changes in monsoon precipitation and mean annual temperature simultaneously over the past 16,000 years using multiple proxies, including isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) and n-alkanes, from an alpine lake in southwestern China. On the one hand, the reconstructed monsoon precipitation shows a long-term increasing trend during the last deglaciation and a gradual decrease during the Holocene, with the highest-humidity period occurring in the early Holocene. Our result displays good consistency with the changes in regional mean annual precipitation, summer precipitation, and monsoon intensity during the last deglaciation and the Holocene. On the other hand, the reconstructed mean annual temperature inferred from the n-alkane proxy shows a long-term warm trend since the last deglaciation. Our result is consistent with the regional reconstruction of both mean annual and summer temperatures during the last deglaciation, while evident seasonal differences were observed for Holocene records with a cooling trend of summer temperature and a warm trend of mean annual temperature. Comprehensive comparison reveals that monsoon precipitation in the Indian monsoon region is mainly related to changes in the Intertropical Convergence Zone (ITCZ) and land-sea thermal contrast controlled by boreal summer insolation. In addition, the increase in temperature during deglaciation is primarily attributed to the escalation of greenhouse gases (GHGs), while the divergent trend of seasonal temperature during the Holocene is mainly attributed to the changes in local seasonal insolation. Our research emphasizes that monsoon precipitation is a summer signature in the Indian monsoon region, which is consistent with the changes in summer temperature, while contrasting with the changes in mean annual temperature. Therefore, it is necessary to consider the seasonal difference in temperature changes when investigating the hydrothermal combination in Indian monsoon regions.

Climate Change Shocks and Credit Risk of Financial Institutions: Evidence from China’s Commercial Banks

ABSTRACT As global climate risk is looming in recent years, the climate risks faced by financial institutions are also increasing. Effectively quantifying and assessing climate-related financial risks is of great significance for financial institutions to establish risk management mechanisms. Accordingly, choosing Chinese commercial bank data from 2007 to 2019, this paper quantitatively evaluates the influence of climate change shock on the banks’ credit risk by taking the annual temperature fluctuation in cities as the core index to characterize the climate change degree. It is found that annual average temperature rise can significantly increase the credit risk level of commercial banks. Heterogeneity analysis indicates that small-scale banks, rural commercial banks, and commercial banks with higher marketization levels are more sensitive to climate change. Further analysis shows summer and autumn temperature changes have the most prominent impact on banks’ credit risk. Moreover, there is no obvious nonlinear relationship or lagged effects between annual temperature change and banks’ credit risk in our dataset.

Threatened European butterflies concentrate in areas of strong climatic change and atmospheric deposition pressure

Land use change, as a result of many local-scale decisions scaling up to large spatial extents, is considered the main threat to European butterflies. The impact of large-scale pressures, such as atmospheric nitrogen deposition or climate change, is less understood or less documented, respectively. However, it is acknowledged that they might reinforce the pressure on already threatened species. To evaluate the additional threat exerted by these pressures we compared their geographical pattern to those of threatened butterflies across Europe. We therefore derived range maps of 383 butterfly species and used two species-specific threat assessments derived from national and European Red Lists. We then used Spearman rank-correlations and beta-regressions to compare two metrics of species threat per 10 × 10 km raster cells with geographical patterns of cumulative nitrogen depositions from 1980 to 2015, as well as the magnitude of change in precipitation sums and temperature means between the decades 1979–1988 and 2004–2013. We found that threatened species tend to concentrate in areas with high nitrogen depositions and pronounced summer temperature changes. In particular, parts of central and eastern Europe were both hotspots of threatened butterflies and hotspots of climatic pressure. This spatial coincidence of the distribution of threatened butterfly species with large-scale patterns of nitrogen depositions and recent climate warming indicates an already considerable risk of regional to continental extinctions that will likely increase further in the future as climate change will most likely intensify. Consequences for area-based conservation measures are discussed.

Future changes of summer monsoon rainfall and temperature over Bangladesh using 27 CMIP6 models

This research aims to investigate the future changes in summer monsoon rainfall and temperature in Bangladesh. The study revealed that INM-CM5-0 is the best model for projecting temperature, while BCC-CSM2-MR is the best model for projecting rainfall over Bangladesh. Using data from a large ensemble of 27 models from CMIP6, the study examined the rainfall and temperature change projections of Bangladesh during the twenty first century relative to the reference period (1981–2014) under SSP2–4.5 and SSP5–8.5. Under SSP2-4.5 and SSP5-8.5, the multi-model ensemble monsoon mean rainfall over Bangladesh will fluctuate between 40 and 260 mm and 100 and 900 mm, respectively. In most parts of the country’s north, northeastern, and western regions, the projected changes in spatial patterns of monsoon rainfall indicate an increase in rainfall. The projected temperature indicated that Bangladesh’s northwest and west-central areas could face the most significant rise in temperatures, surpassing 3.8 °C under SSP5-8.5.

Holocene summer temperature record based on branched tetraethers in Northeast China

The temperature evolution during the Holocene shows conflicting patterns and yields the controversy regarding whether the Holocene followed a warming or cooling trend. Resolving this controversy is critical for understanding the underlying mechanisms of climate change and evaluating global warming on a longer timescale. Here we present a quantitative summer temperature reconstruction based on branched glycerol dialkyl glycerol tetraethers analyzed from a sedimentary sequence retrieved from the volcanic lake Kielguo crater lake in Northeast (NE) China. Our record revealed that the summer temperature in NE China followed a rough cooling trend during ~10–2.2 cal ka BP and increased after ~2.2 cal ka BP. The warmest period appeared at ~10–8.8 cal ka BP with ~15.8°C, and the coldest time occurred at ~2.3 cal ka BP with ~13.4°C. Compared with other temperature records from NE China, we conclude that the summer and winter temperature change trends in NE China were probably controlled by the summer and winter insolation respectively, and the ice volume. The mean annual temperature changes in NE China resulted from the superposition of summer cooling and winter warming during the Holocene, and the decrease in ice volume forcing the increase in mean annual temperatures before ~7–6 cal ka BP. The switch in mean annual temperature changes was probably linked with the collapse of Northern Hemisphere ice sheets.

Divergent trends of changes in annual mean and summer temperature in southwestern China during the Holocene

Divergent trends of changes in annual mean and summer temperature in southwestern China during the Holocene

Changes in surface mass balance and summer temperature from 1961–1990 to 1991–2020 for 37 glaciers with long records

AbstractRecent satellite measurements of glacier mass balance show mountain glaciers all over the world had generally negative mass balances in the first decades of the 21st century. We analyse archived data for surface mass balance and summer temperature for 37 Northern Hemisphere glaciers with data for 1961–2020. We compare mean annual balances for 1961–90 and 1991–2020, and for 25 glaciers explain the changes in annual balance by changes in winter and summer balances. Mean balances 1961–90 were already substantially negative for 19 out of the 25 glaciers. Changes in winter balances from 1961–90 to 1991–2020 average close to zero but changes in summer balance are strongly negative. Mean balance 1991–2020 is strongly correlated with change in summer balance, weakly correlated with winter balance change, and strongly correlated with mean balance 1961–90. We estimate 1991–2020 summer temperature anomalies for the 37 glaciers and confirm that summer temperature anomalies for 1991–2020 were higher for the Alps, by nearly 1.5°C, than for other areas. Substantial variations in the temperature – sensitivity of summer balances for individual glaciers of −0.2 to −1.0 m w.e. a−1 °C−1deserve further study.

Pine Maximum Latewood Density in Semi‐Arid Northern China Records Hydroclimate Rather Than Temperature

AbstractLong records of tree‐ring maximum latewood density (MXD) measurements in conifers have been successfully employed to reconstruct summer temperature changes globally. Yet, the potential of MXD as a proxy in semi‐arid, low‐latitude regions for reconstructing either temperature or hydroclimate variability remains largely unexplored. Here, we developed a MXD data set of Chinese pine from semi‐arid northern China, and investigated its sensitivity to different climate variables. We found that the annual self‐calibrated Palmer Drought Severity Index from previous August to current July displays the strongest influence on the MXD variation. The entire MXD chronology (covering 1736–2020) is highly consistent with nearby tree‐ring‐based annual precipitation and drought reconstructions at decadal timescales, confirming a temporally stable hydroclimate signal in our MXD record. In particular, the rapid wetting trend during the 2010–2020 period is well captured by the MXD data. This novel study has wide implications for future use of tree‐ring density data to reconstruct past climate changes globally.