Annual Balance Research Articles

Wildfire impacts on the carbon budget of a managed Nordic boreal forest

Wildfire is one of the most important disturbances affecting boreal forests. Most previous research on boreal forest fires has occurred in North American forests which have different fire regimes, tree species and are less intensively managed than their Eurasian counterparts. Recent extreme fire years have highlighted the vulnerability of the Nordic boreal forest to climatic shifts that are increasing forest fire frequency and severity. The Ljusdal fire (2018) was one of the largest wildfires in recorded history in Sweden. We established eddy covariance flux towers to track the impacts of this fire on the carbon balance of two Pinus sylvestris sites subject to different fire severities and forest management strategies 1–4 years post-fire. The ‘SLM’ site was a mature stand that experienced low-severity fire (trees survived) followed by salvage-logging and reseeding, whilst the ‘HY’ site was 10 years old when it experienced high-severity fire (all trees killed) then was replanted with seedlings. During the study period, both sites were net carbon sources at the annual scale. It took up to 4 years after the fire until the first day of net CO2 uptake was recorded at each site. We estimated that it will take 13 years (8, 21; mean ± 95 % confidence intervals) after the fire until the sites reach a neutral annual carbon balance. It will take up to 32 years (19, 53) at HY and 46 years (31, 70) at SLM to offset the carbon lost during and after the fire and salvage-logging. In addition, our measurements showed that more carbon was emitted in the first 4 years after the fire compared to the carbon lost from combustion during the fire. Quantifying carbon fluxes during the initial years after fire is therefore crucial for estimating the net impact of wildfire on the carbon budget of boreal forests.

Feasibility analysis of China's medical insurance coverage of assisted reproductive technology

There are millions of patients experiencing infertility in China, but assisted reproductive technology (ART) is performed at the patient's expense and is difficult to afford. With the sharp decline in China's birth rate, there is a growing controversy over the inclusion of ART in medical insurance (MI). This study aims to explore the feasibility of ART coverage by MI for the first time. We obtained basic data such as the prevalence of infertility, the cost of ART, and the success rate in China with the method of meta-analysis and consulting the government bulletin. Then, we calculated the number of infertile couples in China and the total financial expenditure of MI covering ART. Finally, we discussed the feasibility of coverage, and analyzed the population growth and economic benefits after coverage. According to our research results, it was estimated that there were 4.102–11.792 million infertile couples in China, with an annual increase of 1.189–1.867 million. If MI covered ART, the fund would pay 72.313–207.878 billion yuan, accounting for 2–6% of the current fund balance, and the subsequent annual payment would be 20.961–32.913 billion yuan, accounting for 4–7% of the annual fund balance. This was assuming that all infertile couples would undergo ART, and the actual cost would be lower. The financial input‒output ratio would be 13.022. Benefiting from the inclusion of ART in MI coverage, there would be 3.348–9.624 million new live infants, and 8–13% newborns would be born every year thereafter, which means that by 2050, 37–65 million people would be born. Due to its affordable cost, high cost-effectiveness and favourable population growth, it may be feasible to include ART in MI.

Carbon Dynamics of a Coastal Wetland Transitioning to Mangrove Forest

AbstractCoastal wetlands play a vital role in the global carbon cycle and are under pressure from multiple anthropogenic influences. Altered hydrology and land use change increase susceptibility of wetlands to sea‐level rise, saltwater intrusion, tidal flood events, and storm surges. Flooding from perigean spring tides and storm surges rapidly inundates coastal wetlands with saline waters, quickly surpassing vegetation tolerances, leading to shifts in soil microbial respiration, peat collapse, and plant mortality, followed by establishment of salt‐tolerant vegetation. The Southeast Saline Everglades (SESE) is facing many of these pressures, making it a model system to examine the impacts of ecosystem state transitions and their carbon dynamics. Saltwater flooding from Hurricane Irma (2017) initiated a transitional state, where less salt‐tolerant vegetation (e.g., Cladium jamaicense) is declining, allowing halophytic species such as Rhizophora mangle to colonize, altering the ecosystem's biogeochemistry. We utilized eddy covariance techniques in the SESE to measure ecosystem fluxes of CO2 and CH4 in an area that is transitioning to an alternative state. The landward expansion of mangroves is increasing leaf area, leading to greater physiological activity and higher biomass. Our site was presented initially as a small C source (47.0 g C m−2) in 2020, and by 2022 was a sink (−84.24 g C m−2), with annual greenhouse carbon balance ranging from −0.04 to 0.18. Net radiative forcing ranged from 2.04 to 2.27 W m−2 d−1. As the mangrove landward margin expands, this may lead the area to become a greater carbon sink and a potential offset to increasing atmospheric CO2 concentrations.

SWAT‐GL: A new glacier routine for the hydrological model SWAT

AbstractThe hydrological model Soil Water Assessment Tool (SWAT) is widely used in water resources management worldwide. It is also used to simulate catchment hydrology in high‐mountainous regions where glaciers play an important role. However, SWAT considers glaciers in a simplistic way. Although some efforts were done to overcome this limitation, there is no official version available that considers glaciers adequately. This strongly impairs its applicability in glacierized catchments. In this technical note, we propose a novel version of the traditional SWAT, called SWAT‐GL, which introduces (1) a mass balance module and (2) a glacier evolution routine to represent dynamic glacier changes. Mass balance calculations are based on a conceptual degree‐day approach, similar to the snow routine implemented in SWAT. Glacier evolution is realized using the delta‐h (∆h) parameterization, which requires a minimum of data and is thus suitable in data‐scarce regions. The approach allows users to simulate spatially distributed glacier changes. Annual mass balance changes are translated to distributed ice thickness changes depending on the glacier elevation. We demonstrate how SWAT‐GL is technically integrated into SWAT and how glaciers are merged with the existing spatial units. Model code and test data are freely accessible to promote further model development efforts and a wide application. Ultimately, SWAT‐GL aims to make SWAT easily applicable in glacierized catchments without the need of additional tools.

The potential of decentral heat pumps as flexibility option for decarbonised energy systems

Decarbonising the energy system requires high shares of variable renewable generation and sector coupling like power to heat. In addition to heat supply, heat pumps can be used in future energy systems to provide flexibility to the electricity system by using the thermal storage potential of the building stock and buffer tanks to shift electricity demand to hours of high renewable electricity production. Bridging the gap between two methodological approaches, we coupled a detailed building technology operation model and the open-source energy system model Balmorel to evaluate the flexibility potential that decentral heat pumps can provide to the electricity system. Austria in the year 2030 serves as an example of a 100% renewable-based electricity system (at an annual national balance). Results show that system benefits from heat pump flexibility are relatively limited in extent and concentrated on short-term flexibility. Flexible heat pumps reduce system cost, CO2 emissions, and photovoltaics and wind curtailment in all scenarios. The amount of electricity shifted in the assessed standard flexibility scenario is 194 GWhel and accounts for about 20% of the available flexible heat pump electricity demand. A comparison of different modelling approaches and a deterministic sensitivity analysis of key input parameters complement the modelling. The most important input parameters impacting heat pump flexibility are the flexible capacity (determined by installed capacity and share of control), shifting time limitations, and cost assumptions for the flexibility provided. Heat pump flexibility contributes more to increasing low residual loads (up to 22% in the assessed scenarios) than decreasing residual load peaks. Wind power integration benefits more from heat pump flexibility than photovoltaics because of the temporal correlation between heat demand and wind generation.

U.S. monetary policy shocks and bank lending in Latin America: evidence of an international bank lending channel

ABSTRACT We examine the impact of U.S. monetary policy shocks on bank lending in five major Latin American countries where large U.S. banks have limited presence. Our analysis covers annual balance sheet data from 2000 to 2021 for all banks in these nations, utilizing a recently developed measure of U.S. monetary policy shocks by Bu et al. Our findings reveal the existence of an international bank lending channel, with a one-percentage-point increase in the Fed funds rate resulting in an average 80.6 basis-point reduction in domestic bank loan growth in these countries. Liquidity and solvency emerge as crucial factors driving variations in lending behaviour among Latin American banks, with banks exhibiting stronger liquidity and solvency profiles experiencing higher loan supply growth rates.

Visualizing Changes in Global Glacier Surface Mass Balances before and after 1990

Recent satellite measurements of glacier mass balances show mountain glaciers all over the world had generally negative mass balances in the first decades of the 21st century. Mean summer temperatures all over the world rose from the 1961–1990 period to the 1991–2020 period, implying increasingly negative mass balances. We studied archived annual balances for 38 northern hemisphere glaciers to assess changes within the 1961–2020 period. We used a modified double-mass curve to visualize mass balance changes occurring around 1990. Mean balances in 1961–1990 were already small negative for many of the studied glaciers and became even more negative in 1991–2020 for glaciers in the Alps, at high latitudes and in western North America. The largest mass balance changes were for some glaciers in the Alps. We are unable to explain the lack of change in mean balance for one glacier in High Mountain Asia. We found complex changes for eight glaciers in Scandinavia, even including one glacier with a positive balance. We explain these changes by visualizing the deviations in winter and summer balances from their respective 1961–1990 mean values. High winter balances in the 1990s for Scandinavia partly obscured the emerging trend of increasingly negative summer balances, which we expect to continue in the future.

Atmospheric CO2exchanges measured by eddy covariance over a temperate salt marsh and influence of environmental controlling factors

Abstract. Within the coastal zone, salt marshes are atmospheric CO2 sinks and represent an essential component of biological carbon (C) stored on earth due to a strong primary production. Significant amounts of C are processed within these tidal systems which requires a better understanding of the temporal CO2 flux dynamics, the metabolic processes involved and the controlling factors. Within a temperate salt marsh (French Atlantic coast), continuous CO2 fluxes measurements were performed by the atmospheric eddy covariance technique to assess the net ecosystem exchange (NEE) at diurnal, tidal and seasonal scales as well as the associated relevant biophysical drivers. To study marsh metabolic processes, measured NEE was partitioned into gross primary production (GPP) and ecosystem respiration (Reco) during marsh emersion allowing to estimate NEE at the marsh–atmosphere interface (NEEmarsh = GPP − Reco). During the year 2020, the net C balance from measured NEE was −483 g C m−2 yr−1 while GPP and Reco absorbed and emitted 1019 and 533 g C m−2 yr−1, respectively. The highest CO2 uptake was recorded in spring during the growing season for halophyte plants in relationships with favourable environmental conditions for photosynthesis, whereas in summer, higher temperatures and lower humidity rates increased ecosystem respiration. At the diurnal scale, the salt marsh was a CO2 sink during daytime, mainly driven by light, and a CO2 source during night-time, mainly driven by temperature, irrespective of emersion or immersion periods. However, daytime immersion strongly affected NEE fluxes by reducing marsh CO2 uptake up to 90 %. During night-time immersion, marsh CO2 emissions could be completely suppressed, even causing a change in metabolic status from source to sink under certain situations, especially in winter when Reco rates were lowest. At the annual scale, tidal immersion did not significantly affect the net C uptake of the studied salt marsh since similar annual balances of measured NEE (with tidal immersion) and estimated NEEmarsh (without tidal immersion) were recorded.

Elevated Southern Hemisphere moisture availability during glacial periods.

Late Pleistocene ice-age climates are routinely characterized as having imposed moisture stress on low- to mid-latitude ecosystems1-5. This idea is largely based on fossil pollen evidence for widespread, low-biomass glacial vegetation, interpreted as indicating climatic dryness6. However, woody plant growth is inhibited under low atmospheric CO2(refs. 7,8), so understanding glacial environments requires the development of new palaeoclimate indicators that are independent of vegetation9. Here we show that, contrary to expectations, during the past 350 kyr, peaks in southern Australian climatic moisture availability were largely confined to glacial periods, including the Last Glacial Maximum, whereas warm interglacials were relatively dry. By measuring the timing of speleothem growth in the Southern Hemisphere subtropics, which today has a predominantly negative annual moisture balance, we developed a record of climatic moisture availability that is independent of vegetation and extends through multiple glacial-interglacial cycles. Our results demonstrate that a cool-moist response is consistent across the austral subtropics and, in part, may result from reduced evaporation under cool glacial temperatures. Insofar as cold glacial environments in the Southern Hemisphere subtropics have been portrayed as uniformly arid3,10,11, our findings suggest that their characterization as evolutionary or physiological obstacles to movement and expansion of animal, plant and, potentially, human populations10 should be reconsidered.

Effects of birch encroachment, water table and vegetation on methane emissions from peatland microforms in a rewetted bog

This study investigated the influence of vegetation and microforms on methane (CH4) balances of a rewetted bog in north-west Germany. The two study sites are in close proximity on the same former peat extraction area, one dominated by Sphagnum-mosses and the other one by a dense Betula pubescens stand with a high Eriophorum vaginatum cover. The contribution of microforms (hummocks/hollows) to CH4 emissions and the effect of Betula encroachment has been studied. Transparent and opaque chambers were used to measure CH4 fluxes every 3–4 weeks during daytime for one year. For the estimation of annual balances, three methods were compared and the method using water level and soil temperature as explanatory variables was selected. Fluxes were scaled to the site level. The annual emissions per site are and 7.1 ± 1.5 g CH4-C m−2 year−1 at the treed site and 36.1 ± 3.5 g CH4-C m−2 year−1 at the open site, mainly controlled by higher water levels. Highest annual emissions originated from hollows at the open site, but in the vegetation period, hummock emissions tend to be higher. At the tree site, emission differences between the microforms were less pronounced. There were no differences between fluxes from transparent and opaque chambers.

Dry-season length affects the annual ecosystem carbon balance of a temperate semi-arid shrubland

Semi-arid ecosystems have been shown to dominate over tropical forests in determining the trend and interannual variability of land carbon (C) sink. However, the magnitude and variability of ecosystem C balance remain largely uncertain for temperate semi-arid shrublands at the decadal scale. Using eddy-covariance and micro-meteorological measurements, we quantified the interannual variation in net ecosystem production (NEP) and its components, gross primary production (GPP) and ecosystem respiration (Reco, i.e., the sum of autotrophic and heterotrophic respiration), in a semi-arid shrubland of the Mu Us Desert, northern China during 2012–2022. This shrubland was an overall weak C sink over the 11 years (NEP = 12 ± 46 g C m−2 yr−1, mean ± SD). Annual NEP ranged from −66 to 77 g C m−2 yr−1, with the ecosystem frequently switching between being an annual C sink and a C source. GPP was twice as sensitive as Reco to prolonged dry seasons, leading to a close negative relationship between annual NEP and dry-season length (R2 = 0.80, P < 0.01). Annual GPP (R2 = 0.51, P = 0.01) and NEP (R2 = 0.58, P < 0.01) were positively correlated with annual rainfall. Negative annual NEP (the ecosystem being a C source) tended to occur when the dry season exceeded 50 d yr−1 or rainfall dropped below 280 mm yr−1. Increases in dry-season length strengthened the effects of low soil moisture relative to high vapor pressure deficit in constraining NEP. Both GPP and NEP were more closely correlated with C uptake amplitude (annual maximum daily values) than with C uptake period. These findings indicate that dry-season extension under climate change may reduce the long-term C sequestration in semi-arid shrublands. Plant species adapted to prolonged dry seasons should be used in ecosystem restoration in the studied area to enhance ecosystem functions.

Optimizing maize productivity: A sustainable approach integrating straw derivatives and film mulching in rainfed agriculture

Context or problemResource-use inefficiency, environmental degradation and food security are forcing a transformation from conventional to organic and sustainable agriculture. Objective or research questionRealizing synergistic use of light, water, and nitrogen resources for spring maize in a more circular straw utilization model, while comprehensively evaluating the sustainability of the scheme is the key to solving the above problems in rainfed areas, but there are few reports. MethodsAccording to a crop-livestock-biogas digester straw recycling model, straw can be returned to the field directly or in the form of cattle manure after fattening, or cattle manure can continue to be recycled by the digester as the only fermentation substrate, and ultimately returned to the field indirectly in the form of biogas residue. Therefore, according to different levels of straw recycling, four treatments were set up in this study: straw (S), cattle manure (M), biogas residue (BR) and control (CK) for a comparative study of water use efficiency, net solar radiation use efficiency, photosynthetic and leaf characteristics post-anthesis, annual nitrogen balance, spring maize yield, and sustainability index. ResultsThe results showed that straw and its derivatives effectively improve the utilization efficiency of light and water, potentially reducing the adverse effects of factors on yield variability. Maintaining high levels of photosynthetic activity after anthesis was mainly due to the positive effects of organic amendments on nitrogen content per unit leaf area. This led to significant increases in grain yield and harvested index by 5.95% to 13.22% and 3.41% to 6.37%, respectively. However, exogenous organic N addition promoted N2O emission and NH3 volatilization, resulting in a higher N surplus. The sustainable index of each treatment was in the following order: BR>M>CK>S. ConclusionsLong-term organic amendments, especially BR, can effectively improve the utilization and synergistic effects of critical production resources, constituting a high-yielding, efficient and sustainable spring maize population, which is consistent with our hypothesis that the sustainability index is higher in more circular straw utilization. Implications or significanceThis study provides a new plastic film cultivation strategy and evaluation perspective for sustainable spring maize production in the study area or similar areas.

Annual mass-balance time series of Dongkemadi Glacier, 2000–20, from a linear albedo-based model using geodetic data and validated with the glaciological method

Abstract Long-term time series of annual glacier mass balance is important for revealing a glacier's response to regional climate variations. However, for the Tibetan Plateau, time series of annual glacier mass balance with more than 10 consecutive years remains scarce due to the inaccessibility and harsh climate conditions. In this study, we established an albedo-based model to reconstruct annual glacier mass balance for 2000–20 over the Dongkemadi Glacier, based on multitemporal geodetic estimates and annual minimum glacier-wide mean surface albedos. Geodetic glacier mass-balance estimates for 2000–12, 2012–14 and 2014–18 were obtained by comparing glacier surface topographic data. Minimum surface albedos were obtained from the moderate-resolution imaging spectroradiometer daily snow albedo products for 2000–20. The estimated results are supported by the field measurements of annual glacier mass balance. During the early 2000s, we detected a relatively balanced state of glacier mass change, whereas a pronounced mass loss of more than −0.5 m w.e. was found for most years in the 2010s. By analyzing the regional climate variations with the ERA5-Land monthly averaged data, we found that the accelerated glacier mass loss can be attributed to both decreased annual snowfall and increased summer air temperature.

Seasonal variations in the coastal beach profiles at Calabonita Beach in AL Hoceima Bay, Morocco

Sandy beaches are among the Earth's most dynamic natural environments, with wave action and swells critically influencing the energetics of erosion and sediment transport. This energy's temporal and spatial distribution significantly affects coastal morphological evolution. This study investigates the seasonal morphodynamic variability and short-term alterations at Calabonita Beach, located within Al Hoceima Bay, by analyzing topographic profiles collected from June 2022 to May 2023. Findings indicate that Calabonita Beach is relatively narrow, averaging a width of 27.53 meters with a slope of 6.82%. The annual vertical movement balance was found to be negative, showcasing a distinct pattern of sediment accumulation during autumn and increased erosion during winter. These results highlight the beach's dynamic nature, governed by natural processes and human activities, underscoring the intricate interplay between accumulation and erosion patterns.

Assessment and analysis of correlation between remote sensing albedo in ablation season and annual mass balance for glaciers in High Mountain Asia

Assessment and analysis of correlation between remote sensing albedo in ablation season and annual mass balance for glaciers in High Mountain Asia

Shallow geothermal systems in dense urban areas: The issue of thermal interference and long-term sustainability

Shallow geothermal systems, namely Ground Source Heat Pumps (GSHP) and Ground Water Heat Pumps (GWHP), are expected to give an increasing contribution to the decarbonization of the buildings climatization sector. A fully sustainable use should guarantee fair access to the shallow geothermal sources for new systems, given the potential thermal interference among neighbouring ones in dense urban areas, and address environmental concerns related to thermal pollution of ground and groundwater. In this paper the state of the art concerning environmental concerns, regulation approaches and sustainability metrics is firstly reported. Then, focusing on closed-loop systems, a simulation case study is developed to study the long-term thermal footprint in the ground. The Energy Imbalance indicator, summarizing the annual energy balance in the ground, drives the thermal drift produced by the bore-field and is therefore proposed as the main sustainability indicator. For given ground conditions, a maximum Energy Imbalance is identified, which limits the thermal perturbation distance to the borehole spacing and minimizes thermal interference with other systems.

Transformation of Level of Humidification in the Eastern Part of Cuba

The work is devoted to analysing the transformation of humidification in a changing climate in the eastern part of Cuba, the case of Holguin (east of the island). The importance of the study is related to the need to study precipitation trends in certain regions. Based on the analysis of the long-term dynamics of annual precipitation values, relative humidity, and the number of days with precipitation, trends in the degree of moisture in the east of the island was established. The practical significance of the work lies in identifying and developing long-term weather forecasts and planning the economic and recreational development of the territory. The 1970–2020 period was considered. Changes in the amount of precipitation and days with precipitation were analysed. The moisture coefficient for the territory was calculated. The wettest and driest periods were identified, with the wettest being from 1981 to 1985 and the driest being from 1991 to 1995. The average rainfall for the wettest period was 1365 mm, while the average rainfall for the driest period was 335 mm. There was an increase in the number of days with precipitation from 39 days (1970) to 150 (2007). The maximum values of days with precipitation occurred in the period from 2006 to 2010. The calculated balance of humidification of the territory revealed heterogeneity of conditions of humidification of the territory. The maximum moisture deficit falls in the period from February to April, and the minimum – in June. The annual moisture balance was -653 mm. The territory is experiencing a lack of moisture.

Nitrogen Budget of South Korea from 2015 to 2019 Including Gaseous Nitrogen Oxides

Objectives : The study was aimed to systematically understand the nitrogen budget from 2015 to 2019, and to determine the annual nitrogen balance in South Korea.Methods : The nitrogen budget was calculated by classifying into agricultural and livestock, city, and forest areas. The nitrogen input was estimated from deposition, biological fixation, agricultural water, inorganic chemical fertilizer, compost, feedstuff, produced crops, imported grocery, and fuel consumption. The nitrogen output was estimated by considering denitrification, volatilization, ground water runoff, land and crop absorption, sewage disposal, drainage, forest uptake, and nitrogen oxide (NOx) emissions.Results and Discussion : The annual nitrogen budget from 2015 to 2019 showed the input as 6,107,449 ton/yr, 6,144,666 ton/yr, 6,245,240 ton/yr, 6,281,552 ton/yr, 5,993,347 ton/yr and the output as 1,346,587 ton/yr, 1,369,119 ton/yr, 1,365,327 ton/yr, 1,378,940 ton/yr, 1,365,994 ton/yr, respectively. The NOx, highly contributing to change in the nitrogen budget, was caused by human activities such as vehicles, business places, and power plants. More than 32% of the total nitrogen budget was caused by NOx in every year.Conclusion : The nitrogen budget continued to increase in the 2010s because of the increase in food and fuel consumption by urbanization. However, the nitrogen budget declined in 2019 due to the effort such as emission regulations and the use of alternatives as the awareness of environmental pollution gradually increased. Therefore, the appropriate institution should be established and actively implemented to reduce the nitrogen effectively.

Annual to seasonal glacier mass balance in High Mountain Asia derived from Pléiades stereo images: examples from the Pamir and the Tibetan Plateau

Abstract. Glaciers are crucial sources of freshwater in particular for the arid lowlands surrounding High Mountain Asia. To better constrain glacio-hydrological models, annual, or even better, seasonal information about glacier mass changes is highly beneficial. In this study, we evaluate the suitability of very-high-resolution Pléiades digital elevation models (DEMs) to measure glacier mass balance at annual and seasonal scales in two regions of High Mountain Asia (Muztagh Ata in Eastern Pamirs and parts of western Nyainqêntanglha, south-central Tibetan Plateau), where recent estimates have shown contrasting glacier behaviour. The average annual mass balance in Muztagh Ata between 2019 and 2022 was −0.07 ± 0.20 m w.e. a−1, suggesting the continuation of a recent phase of slight mass loss following a prolonged period of balanced mass budgets previously observed. The mean annual mass balance in western Nyainqêntanglha was highly negative for the same period (−0.60 ± 0.15 m w.e. a−1), suggesting increased mass loss rates compared to the approximately previous 5 decades. The 2022 winter (+0.13 ± 0.24 m w.e.) and summer (−0.35 ± 0.15 m w.e.) mass budgets in Muztagh Ata and western Nyainqêntanglha (−0.03 ± 0.27 m w.e. in winter; −0.63 ± 0.07 m w.e. in summer) suggest winter- and summer-accumulation-type regimes, respectively. We support our findings by implementing the Sentinel-1-based Glacier Index to identify the firn and wet-snow areas on glaciers and characterize the accumulation type. The good match between the geodetic and Glacier Index results supports the potential of very-high-resolution Pléiades data to monitor mass balance at short timescales and improves our understanding of glacier accumulation regimes across High Mountain Asia.

To Shade or not to Shade (and how)? Annual heating energy balance and internal temperature in low energy houses in Wrocław, Poland.

One of the important areas of occupant–building fabric interaction with IEQ consequences is windows’ shading. The relevance of shading has been explored through modeling studies in the context of energy, daylighting and thermal comfort, typically aiming to inform the design stage. In owner occupied housing the architectural design sets the scene for subsequent residents’ decisions concerning windows treatment. Here, based on varied treatments for 20m2 living room window observed during an in-depth building performance evaluation in same homes, dynamic modeling in TRNSYS is used to establish the related heating loads and internal temperatures. The results allow to rank five shading usage scenarios for three physical settings, namely lack of shading, external blind and internal curtain on lower half of the window, in terms of their overheating mitigation potential, based on simplified assumptions for heating, ventilation and shading practices. The modelling points towards severe overheating issue and crucial impact of shading usage patterns on its mitigation. Yearly modelled share of overheating hours (>26 °C) are almost double for unshaded scenario compared to the most effective shading strategy (25% and 13%). The simulation contributes to understanding of the field monitoring results where the unshaded living rooms experience more severe overheating, and the two shading settings in place are associated with comparable internal thermal conditions, respectively 22% vs. 5% and 6% of yearly share of overheating hours. The simplification of human-HVAC-building interaction model likely obfuscates solar heat gain control contribution to heating load.