International Mountain Conference

Abstract ID 148 | Date: 2022-09-14 10:10 – 10:20 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Napoli, Anna (1,2,3); Von Hardenberg, Jost (4,5); Parodi, Antonio (3); Pasquero, Claudia (5,6)

Climate change has a strong impact on the environment in mountain areas, especially since mountain ecosystems depend on climatic conditions that vary with altitude. In recent years, it has become clear that warming strongly depends on elevation. In this study, we examine projected climate change in the Greater Alpine Region using the Weather Research Forecasting (WRF) model. Historical 30-year simulations (1979-2008) and climate change projections (2039-2068) were performed at high spatial resolution (4 km grid spacing) and with initial and boundary conditions provided by the global EC-Earth model. A focus on the altitudinal dependence of historical and future ETCCDI Climate Change indices is presented here: the results indicate that both temperature and precipitation are affected by climate change with an altitude dependence changing seasonally. Physical mechanism at the base of those differences are discussed.

Abstract ID 742 | Date: 2022-09-14 10:20 – 10:30 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Ødegård, Rune Strand (1); Isaksen, Ketil (2)

Global warming is projected to result in more winter warming events. In cold climates such events can lead to the formation of thick internal ice layers in the snowpack or ice layers at the ground surface, impacting the ground vegetation. In the high-altitude areas of central Southern Norway ice layers will restrict access to winter fodder for reindeers and mosk oxen. There is also an impact on the permafrost ground thermal regime. The analysis is linked to the GLORIA-Norway project. The objective of this project is to monitor physical factors and vegetation on a local scale over regional gradients under a changing climate. GLORIA-Norway is part of the GLORIA project (Global Observation Research Initiative in Alpine Environments – www.gloria.ac.at).

The dataset used for the analysis is a subset of the gridded 1 km dataset (seNorge, from 1957) and two meteorological stations. Dombås (from 1864) is a valley station at 638 masl. and Fokstugu (from 1954) is situated on a mountain plateau at 973 masl. The winter season was defined November-March, and we have used five different climate indices following the suggestions of Vikhamar-Schuler et al. (2016) in addition to a modified Warm Spell Duration Index (WSDI). The parameters suggested by Vikhamar-Schuler was number of meltdays, accumulated positive degree days, number of meltdays with precipitation and accumulated precipitation for meltdays.

The analysis was conducted in 10-year intervals. All parameters show a significant increase during the last 30 years compared to the previous 30-year period. The 1920's and 1930's also show high values, but less than the last 30 years. The strongest signal was found for the Warm Spell Duration Index. In the original version the WDSI use daily maximum temperature as input. For this application we tested average daily temperature as input because formation of ice layers normally requires a longer period of melt.

Comparison of the valley station (Dombås) and the mountain plateau station (Fokstugu) show similar timeseries, but the mountain station has a more consistent increase since 1990's. This applies to winter- and summer season. The gridded data show a strong increase in the number for meltdays above approx. 1600 masl.

Reference:

Vikhamar-Schuler D, Isaksen K, Haugen JE, Tømmervik H, Luks B, Schuler T, Bjerke J. 2016. Changes in winter warming events in the Nordic Arctic Region. Journal of Climate 29, doi: 10.1175/JCLI-D-15-0763.1

Abstract ID 922 | Date: 2022-09-14 10:30 – 10:40 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Castillo, Sonia (1,2); Titos, Gloria (1,2); Casquero-Vera, Juan Andrés (1,2,3); Rejano, Fernando (1,2); Casans, Andrea (1,2); Ruiz-Peñuela, Soledad (1,2); Abril-Gago, Jesús (1,2); Olmo-Reyes, Francisco José (1,2); Alados-Arboledas, Lucas (1,2)

The Andalusian Global ObseRvatory of the Atmosphere (AGORA) is located in Southern Spain and includes several experimental sites. The observatory consists on multi-instrumental sites that develop activities contributing to increase our knowledge of the atmospheric processes and their impact on the Earth's Climate. AGORA include a high-altitude mountain station, Sierra Nevada Station (SNS, 37.10ºN, 3.39ºW, 2500 m asl), located at around 20 km from Granada city (680m asl), in the Sierra Nevada National Park. The high mountain station allows for the characterization of regional and long-range transport episodes as well as for local phenomena that might affect the air quality of this natural environment. The instrumentation deployed at SNS allows for the characterization of aerosol optical and microphysical properties and the study of cloud formation processes.

A multi-instrumental field campaign, BioCloud, was performed at SNS in summer 2021. In the frame of this campaign, a time-of-flight aerosol chemical speciation monitor (ToF-ACSM, Aerodyne Research Inc.) was deployed from 10 June to 15 July 2021 to measure real-time inorganic (nitrate, sulphate, ammonium and chloride) and organic submicron compounds (PM₁). Co-located measurements, including real-time gaseous species (NO, NO₂, SO₂ and O₃), in combination with an Aethalometer (AE33, Magee Scientific) for the determination of the equivalent black carbon (eBC), and off-line PM10 chemical analysis (high volume samplers), were also carried out. With this infrastructure, total mass of 60 chemical species, diurnal variations, relative species contributions and sources of organic aerosol (OA) were determined.

The chemical PM₁ pool was mainly comprised of secondary aerosols, being the organic aerosol (OA) the key component of submicron particulate matter during the whole campaign. The mean PM₁ concentration in the campaign was 4 µg/m³, distributed in 3 µg/m³ of OA, and 0.24, 0.27, 0.01 and 0.25 µg/m³ of nitrate, sulphate, chloride and ammonium, respectively. The large fraction of organic aerosols is principally originated from biogenic sources. The diurnal cycle of the submicron species shows a clear production of secondary aerosols during the afternoon hours. The intensity of photooxidation processes at these hours, the pollutant upward transport from Granada city and the atmospheric boundary layer growth dynamics, modelled the diurnal cycle of the species.

This work is part of Smart EcoMountains, the Thematic Center on Mountain Ecosystems of LifeWatch-ERIC.

Abstract ID 239 | Date: 2022-09-14 10:40 – 10:50 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Ali, Shaukat

Many efforts are underway to generate accurate local scale high resolution reference gridded data for mountain regions where data is generally sparse. This study is one of the efforts under the project of APN named "Towards robust projections of climate extremes and adaptation plans over South Asia" which aims to prepare local scales (5 km) reference data for the mountainous regions of Pakistan and Nepal that will be used to downscale CMIP6 data and produce local information on climate extremes and identify vulnerable regions.

In the first step, quality control was conducted to station data using both an objective and subjective technique. ERA5 data were adjusted for bias using observation data. To obtain a grid dataset with 5 km of horizontal resolution, we combine observed data with regularly spaced data (from bias-corrected ERA5 for instance) using kriging. ERA5 are excluded from the regions where an observation stations are available since station data has a higher weight. For the case of temperature, to minimize the errors that occur during the interpolation in regions with scarcity of observed data (in mountainous region) and rugosity topography. For this reason, the temperature is adjusted taking into account the estimated average of the Lapse Rate of Temperature (LRT). This adjustment takes into account the topography of the region where the interpolation is being calculated. For this purpose, a digital elevation model (high resolution) – Global 30 Arc-Second Elevation (GTOPO30) from U.S. Geological Survey (USGS). Following the preparation of the reference data, a seasonal maps are prepared to analyze the region's climatology, as well as local information on climatic extremes to identify vulnerable regions.

Abstract ID 450 | Date: 2022-09-14 10:50 – 11:00 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Surya, Gautam (1); Elsen, Paul (1); Grantham, Hedley (1); Ruane, Alex (2); Phillips, Meridel (3); De Mel, Manishka (3); Poya Faryabi, Sorosh (1)

Biodiversity is not randomly distributed. We have long been aware that certain assemblages of species tend to co-occur, giving rise to hierarchical classifications of biodiversity from ecoregions to biomes. Ecoregions in particular are frequently used in conservation analyses and protected area planning as a proxy for biodiversity representation. However, these analyses generally treat ecoregions as static. Yet at the same time, there is an abundant literature on the projected changes of the distributions of individual species and guilds of species in the context of climate change. This is particularly relevant in montane regions, where the velocity of climate change is expected to be highest with large resulting perturbances to biodiversity assemblages.

The Panj-Amu River Basin of northeast Afghanistan is a topographically complex region comprised of a mixture of grassland, forest and desert ecoregions, the specific ecological contexts of which are critical to supporting the livelihoods of the area's communities. Using high-resolution downscaled models, we show that large areas of this landscape are expected to transform over the coming century, both at the ecoregion and the biome level. These findings highlight the need to explicitly consider climate change and adaptation in conservation planning analyses that incorporate ecoregions as measures of representation. These findings also highlight the precarious nature of the connection between ecological context and human livelihoods, and create a spatially explicit pathway for better understanding local vulnerabilities in the face of a changing world.

Abstract ID 764 | Date: 2022-09-14 11:00 – 11:10 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Mazan, Emily A. (1); Mateo, Emilio I. (1); Mark, Bryan G. (1); Hellström, Robert Å. (2)

The Cordillera Blanca, Peru (10 degrees S) and the Snake Range of the Great Basin National Park, Nevada (40 degrees N) are separated by 50 degrees of latitude. Intercomparing the temperature and moisture trends of these two mountainous regions fosters an understanding of latitudinal variability in elevation dependent warming within the American Cordillera. Low-cost lascar sensors were installed along the slopes of these mountain regions. Four sensors range from 3955 m to 4700 m in the Cordillera Blanca and 29 from 1639 m to 3976 m in the Great Basin National Park. These networks of sensors collect hourly temperature, dewpoint, and relative humidity data providing insight on elevation dependent trends from 2006-2018. Within this period, daily minimum temperatures in Nevada increased by 2.1°C. An upward trend in daily temperatures at higher elevations in Peru is observed with daily minimum temperatures increasing more than 1°C at 4700 m. In both regions, greater rates of warming were observed at higher elevations. In Peru, there were increasingly positive rates of change in dewpoint and relative humidity with height. Just as the temperature trends, the increase in humidity was most apparent at higher elevations, especially above 4500 m. Stations at lower elevations exhibited more daily and seasonal variations in humidity trends than temperature trends. The most evident increasing humidity trends are associated with the wet season.

Abstract ID 106 | Date: 2022-09-14 11:10 – 11:20 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Palazzi, Elisa (1,2); Toledo, Osmar (3); Cely Toro, Iván Mauricio (3); Mortarini, Luca (2)

Several studies report on elevation-dependent warming (EDW), i.e., when warming rates change with elevation. This study assesses future EDW in the Andes, using an ensemble of regional climate model simulations belonging to the CORDEX experiment. EDW was assessed by calculating the (minimum and maximum) temperature difference between the end of the century (2071-2100) and the period 1976-2005 and relating it to the elevation. For the maximum temperatures, a positive EDW (enhancement of warming rates with elevation) was identified in both the western and eastern side of the tropical and subtropical Andes and in all seasons. For the minimum temperature, while a positive EDW was identified in the Subtropics (particularly in the western side of the chain), the Tropics are characterized by a negative EDW throughout the year. The tropical boundary marks a transition between discordant EDW behaviours in the minimum temperature. In the Tropics, EDW drivers were found to be different for the minimum temperature (Tmin) and for the maximum temperature (Tmax). Changes in Tmin are mostly associated with changes in downward longwave radiation, while changes in Tmax are mainly driven by changes in downward shortwave radiation. This might explain the opposite EDW signal found in the tropical Andes during daytime and nighttime. Changes in albedo are an ubiquitous driver for positive EDW in the Subtropics, for both the minimum and the maximum temperature. Changes in longwave radiation and humidity are also EDW drivers in the Subtropics but with different relevance throughout the seasons and during daytime and nighttime. Besides the dependence on the latitude, we found that the western and eastern sides of the Cordillera might be influenced by different EDW drivers.

Abstract ID 373 | Date: 2022-09-14 11:20 – 11:30 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Potter, Emily Ruth (1,2); Fyffe, Catriona (3); Orr, Andrew (4); Quincey, Duncan (2); Ross, Andrew (5); Rangecroft, Sally (6,7); Medina, Katy (8); Burns, Helen (5); Llacza, Alan (9); Jacome, Gerado (9); Hellström, Robert (10); Castro, Joshua (11); Hosking, J. Scott (4,12); Cochachin, Alejo (13); Klein, Cornelia (14,1); Loarte, Edwin (8); Pellicciotti, Francesca (3,15)

Precipitation, snow and ice melt from Andean river basins provide a crucial water source to mountain and downstream communities equally. Precipitation and temperature changes due to global climate change are likely to affect agriculture, hydropower generation and hazard risks, but are poorly constrained, especially in future projections.

Here we focus on two heavily glacierised regions of the Peruvian Andes, the Cordillera Blanca, and the Cordillera Vilcanota-Urubamba, to assess projected changes in extreme meteorological events and droughts. Previous work suggests increasing temperatures in both regions in the 21^st century, with contrasting projections of precipitation trends. There has been little focus, however, on how extremes in precipitation and temperature might vary in the future. Having created a bias-corrected regional climate model from 1980-2018, we use empirical quantile mapping to statistically downscale 30 CMIP5 models. This ensemble is analysed to determine future changes in climate extremes.

Both minimum and maximum daily temperatures are projected to increase in the from 2018 to 2100. This leads to a large reduction in the number of frost days in both regions, and suggests that under a high-emissions scenario, almost every day in the late 21^st century will be in the 90^th percentile of temperatures experienced during 1980-2018. The number of wet and dry days is not projected to change, but precipitation falling on very wet days (in the 95^th percentile of the 1980-2018 period) is projected to increase significantly.

Lastly, we consider changes in future meteorological droughts using the standardised precipitation evapotranspiration index (SPEI) which considers potential evapotranspiration, as well as precipitation. We estimate potential evapotranspiration from temperature projections, using the Hargreaves method. Despite projected precipitation increases, temperature increases leading to an increase in evaporation may be large enough to increase meteorological droughts in the future, with the total number of drought months projected to almost double under high emission scenarios by the end of the 21^st century. In a region that already experiences water stress and hazards, these changes to both extreme rainfall and drought could have a significant impact for communities in the Peruvian Andes, and for the downstream urban areas and industry that rely on mountain river flow.

Abstract ID 841 | Date: 2022-09-14 11:30 – 11:40 | Type: Oral Presentation | Place: THEOLOGIE – SRVI |

Schoessow, Forrest; Mark, Bryan; Thompson, Lonnie; Howat, Ian

Throughout the tropical Peruvian Andes, the cryosphere is destabilizing as climate warms, exposing downstream populations to complex challenges of increased geo-hazards and altered hydrology. The Cordillera Blanca, Earth's most glacierized tropical range, reaches 6768 masl at the summit of Nevado Huascaran. The extent to which climate change will affect this high-mountain environment or might be augmented with elevation remains unclear, especially since maintaining direct measurements is not feasible. Geodetic and glaciological mass balance measures remain scarce in the accumulation zone, and gridded measures of glacier surface characteristics spanning climatically relevant timescales do not exist. Nevertheless, glacier mass balance fluctuations in the tropical Andes have great potential to aid investigations of elevation-dependent climate change and local feedback processes.

This research helps fill these high-altitude knowledge gaps by leveraging four decades of in situ and remote observational data alongside recent computational advances to characterize the mass balance fluctuations of individual glaciers across the Cordillera Blanca and test tropical climate-glacier linkage hypotheses. In 2019, we conducted a series of sustained, highly coordinated observations from instruments in space, sky, and on the ground — including glaciological, geophysical, and geodetic measures collected in the Col and on the summit of Nevado Huascaran, as well as time-synchronous measures coordinated and aligned with IceSat-2. These in situ observations provided the ground-control and validation information necessary to extract DEMs from sub-meter satellite imagery aligned using high-precision airborne lidar and SRTM reference DEMs. From this novel time series, we extracted 63 unique epochs of high-resolution, gridded geodetic mass balance measures across the accumulation zone. We used Bayesian regression and cross-correlational frameworks to quantify the influence of glacier-specific morpho-geometric characteristics versus local-to-large-scale climate factors in determining glacier response patterns.

Here, we present recent seasonal-to-multidecadal patterns of elevation-dependent variables influencing tropical glacier-climate interactions alongside new insights concerning high-elevation accumulation trends in the tropical Andes evidenced by snow pit, ice core, geodetic, geophysical, and meteorological station observations. We identify the principal factors governing changes in glacier surface area versus mass balance and discuss differences between individual glacierized catchments that, despite sharing a similar climate, exhibit varied glacier responses. We discuss the complex nested feedback mechanism components modulating glacier changes along latitudinal, longitudinal, and altitudinal gradients. This research also identifies clear linkages between glacier response patterns, seasonal temperature and precipitation variability, and large-scale climate phenomena. We conclude by highlighting these distinct seasonal sensitivities of tropical glaciers to short versus longer-term climate variability.

Abstract ID 907 | Date: 2022-09-14 15:15 – 15:17 | Type: Poster Presentation | Place: SOWI – Garden |

García-Valdecasas Ojeda, Matilde (1,2); Peinó Calero, Eric (1); Romero Jiménez, Emilio (1); Yeste Donaire, Patricio (1,2); Rosa Cánovas, Juan José (1,2); Rodriguez Brito, Alicia (1); Gámiz Fortis, Sonia Raquel (1,2); Castro Díez, Yolanda (1,2); Esteban Parra, María Jesús (1)

The climate of Sierra Nevada (SN), located in southeastern Spain, affects many important features for the living systems that inhabit it as well as the water resources of a region with semi-arid characteristics. The climate change impacts in this region can be especially aggravated by its mountain condition in a Mediterranean area, which makes it a double climate change hotspot.
This work describes climate variability and recent trends as well as climate change projections for far future (2070-2100) for the main climate variables in SN. Precipitation is characterized by marked inter and intraannual variability, a typical condition of the Mediterranean climate. The North Atlantic Oscillation (NAO) mainly drives the variability over the western part; meanwhile the eastern part is more dominated by Mediterranean depressions, and particularly by the Western Mediterranean Oscillation (WeMO). On the other hand, the altitude has only a minor effect on rainfall distribution. The influence of altitude is clear for both maximum and minimum temperature, being, in general, lower for minimum temperature. Both temperatures show increasing trends during the last decades, although with a more generalized spatial pattern for minimum ones. According to this increase, significant positive trends are found for extreme event indices associated with warm days as well as a marked enhancement of potential evapotranspiration (ET0). There is a prevailing decrease in annual and winter precipitation for the whole area, related with significant negative trends over the west of SN. However, the Standardized Precipitation Index (SPI) shows an increase in drought events being the enhanced drought conditions related to increased atmospheric demand.
Climate projections from a set of Euro-CORDEX simulations show a clear warming and drier conditions over SN, especially for the RCP8.5 scenario. The ensemble mean reveals reductions in evapotranspiration for most of the SN, with only moderate increases at higher altitudes in winter and spring, probably related to an increase in ET0 and a rise in temperature. Soil moisture is expected to decrease across SN under RCP8.5. Drought events are likely to become longer and more frequent in the future throughout the entire region.

This work is part of Smart EcoMountains, the Thematic Center on Mountain Ecosystems of LifeWatch-ERIC.

Abstract ID 821 | Date: 2022-09-14 15:17 – 15:19 | Type: Poster Presentation | Place: SOWI – Garden |

Stöckhardt, Marie (1,2); Hänchen, Lorenz (1); Thomas, Christoph (2); Maussion, Fabien (1); Wohlfahrt, Georg (1)

On average, surface temperatures are rising globally, but the pace of warming varies with regional factors. Rates of warming are expected to increase with elevation, a phenomenon referred to as elevation-dependent warming (EDW). Drivers of EDW include albedo changes due to an upward migration of snow- and treelines, as well as a rise of the condensation level and water vapour changes.

Amplified warming in high altitudes can have a great impact on mountain ecosystems and agriculture, which are particularly sensitive to changes in climate. The cryosphere is also impacted by EDW, with consequences for downstream water availability. While various studies have reported the presence of EDW, it is still unclear whether the phenomenon occurs in all mountain ranges or at all elevations. Research on EDW is made more difficult by sparse station observations: satellite data can be used to overcome these limits and facilitate analysis on the scale of whole mountain ranges and for longer time periods.

In this study, we used 20 years of day- and nighttime products of land surface temperature (LST) observations from the Moderate Resolution Imaging Spectroradiometers (MODIS) on board of the TERRA satellite. The Andes were chosen as study area due to their latitudinal and altitudinal extent, which covers a wide range of climate and socio-economic zones.

We found warming to occur predominantly in the midlatitudes with an associated pattern of elevation-dependence. In contrast, the tropical Andes show both cooling and warming patterns with no clear elevation dependence. Additionally, seasonal variations of the magnitude and sign of the trends are more pronounced in the tropical latitudes than in the southern Andes. Trends were occurring more frequently during nighttime than during daytime. Our results depict the complex nature of EDW and call for further process-based studies supported by remote sensing data.

Abstract ID 920 | Date: 2022-09-14 15:19 – 15:21 | Type: Poster Presentation | Place: SOWI – Garden |

Castillo, Sonia (1,2); Cazorla, Alberto (1,2); Pey, Jorge (3); Alados-Arboledas, Lucas (1,2)

National Parks are usually areas with unique ecosystems protected by regulations due to their geological/biological richness. Sierra Nevada, in the southeast of the Iberian Peninsula, is one of the high-altitude National Parks of the Spanish network. Due to its geographical position, this area registers a sub-tropical climatic context and have an ideal location considering the role of distance to the Saharan dust as a source of mineral particulate matter to the atmosphere. The deposition fluxes of these natural particles can contribute significantly to the ecosystems by providing elements of biogeochemical relevance, such as N, Ca, Mg, K, P and Fe.

Atmospheric deposition is recorded from November 2017 to October 2021 in a high mountain station (SNS, 37.10ºN, 3.39ºW, 2500 m asl), belonging to the Andalusian Global ObseRvatory of the Atmosphere (AGORA), in the Sierra Nevada National Park, at around 20 km from Granada city (680m asl). Wet, dry and bulk deposition for the entire period is analysed in this study to discern the impact of African dust in the overall deposition flux. To this end, North African events (NAF) have been identified and their contributions have been quantified.

The annual atmospheric bulk deposition in SNS account between 10-20 g/m².year. This atmospheric particle contribution is influenced by the number and intensity of the NAF events. The high number of NAF events in Sierra Nevada (25-35 % of the days) and the intensity of these events, explain the elevated annual dust load registered. Furthermore, the phenomenology of the dust deposition is also an important controlling factor of the deposition mode contribution. The annual contribution by dry-deposition mode accounts around 6-8 g/m².year whereas the wet-deposition mode can vary from 5 to 12 g/m².year. The large variability observed in the contribution of the wet-deposition mode is mainly related to the number of the rain events. Despite the annual precipitation mean in SNS is around 500 mm, differences from 1000 mm to 400 mm of precipitation has been registered in the study period.

The larger recurrence of the dry-deposition mode in SNS affect the insoluble/soluble species relation. In SNS the insoluble fraction account for 65-70% of the total mass deposited, while the soluble fraction only account 30-35%. NAF events can contribute 4-5 g/m².year to the insoluble fraction whereas in periods without NAF events, the contribution decrease to 0.3-0.4 g/m².year.

This work is part of Smart EcoMountains, the Thematic Center on Mountain Ecosystems of LifeWatch-ERIC.

Abstract ID 253 | Date: 2022-09-14 15:21 – 15:23 | Type: Poster Presentation | Place: SOWI – Garden |

Rottler, Erwin (1); Strasser, Ulrich (2); Bronstert, Axel (1)

Diminishing seasonal snow covers are among the most apparent impacts of rising temperatures in mountainous areas. Changes in seasonal snowpacks have the potential to fundamentally alter the viability of mountain ecosystems all over the world. In return, diminishing snowpacks can reinforce positive temperature trends by snow albedo feedback mechanisms (SAF). A profound understanding of SAF is key to assess future changes of temperature characteristics along the elevation range. In this study, we aim to track the impact of SAF on temperature in space and time using high resolution gridded observational datasets for the area of Trentino-South Tyrol (north-eastern Italian Alps). Particular focus is on the quantification and visualization of potential and actual reinforcement of rising temperatures by SAF depending on elevation. First results confirm the potential of selected datasets to resolve historic changes in snow cover and temperatures in high temporal and spatial resolution.