scholarly journals Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs

2015 ◽  
Vol 15 (16) ◽  
pp. 9435-9453 ◽  
Author(s):  
G. Shi ◽  
A. M. Buffen ◽  
M. G. Hastings ◽  
C. Li ◽  
H. Ma ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Mass Fraction ◽  
Stratospheric Ozone ◽  
Warm Season ◽  
Cold Season ◽  
Depth Interval ◽  
Depositional Processes ◽  
Antarctic Snow ◽  
Exponential Change ◽  
The Impact

Abstract. Snowpits along a traverse from coastal East Antarctica to the summit of the ice sheet (Dome Argus) are used to investigate the post-depositional processing of nitrate (NO3−) in snow. Seven snowpits from sites with accumulation rates between 24 and 172 kg m−2 a−1 were sampled to depths of 150 to 300 cm. At sites from the continental interior (low accumulation, < 55 kg m−2 a−1), nitrate mass fraction is generally > 200 ng g−1 in surface snow and decreases quickly with depth to < 50 ng g−1. Considerably increasing values of δ15N of nitrate are also observed (16–461 ‰ vs. air N2), particularly in the top 20 cm, which is consistent with predicted fractionation constants for the photolysis of nitrate. The δ18O of nitrate (17–84 ‰ vs. VSMOW (Vienna Standard Mean Ocean Water)), on the other hand, decreases with increasing δ15N, suggestive of secondary formation of nitrate in situ (following photolysis) with a low δ18O source. Previous studies have suggested that δ15N and δ18O of nitrate at deeper snow depths should be predictable based upon an exponential change derived near the surface. At deeper depths sampled in this study, however, the relationship between nitrate mass fraction and δ18O changes, with increasing δ18O of nitrate observed between 100 and 200 cm. Predicting the impact of post-depositional loss, and therefore changes in the isotopes with depth, is highly sensitive to the depth interval over which an exponential change is assumed. In the snowpits collected closer to the coast (accumulation > 91 kg m−2 a−1), there are no obvious trends detected with depth and instead seasonality in nitrate mass fraction and isotopic composition is found. In comparison to the interior sites, the coastal pits are lower in δ15N (−15–71 ‰ vs. air N2) and higher in δ18O of nitrate (53–111 ‰ vs. VSMOW). The relationships found amongst mass fraction, δ15N, δ18O and Δ17O (Δ17O = δ17O–0.52 × δ18O) of nitrate cannot be explained by local post-depositional processes alone, and are instead interpreted in the context of a primary atmospheric signal. Consistent with other Antarctic observational and modeling studies, the isotopic results are suggestive of an important influence of stratospheric ozone chemistry on nitrate formation during the cold season and a mix of tropospheric sources and chemistry during the warm season. Overall, the findings in this study speak to the sensitivity of nitrate isotopic composition to post-depositional processing and highlight the strength of combined use of the nitrogen and oxygen isotopes for a mechanistic understanding of this processing.

scholarly journals Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs

2014 ◽  
Vol 14 (23) ◽  
pp. 31943-31986 ◽  
Author(s):  
G. Shi ◽  
A. M. Buffen ◽  
M. G. Hastings ◽  
C. Li ◽  
H. Ma ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Mass Fraction ◽  
Warm Season ◽  
Cold Season ◽  
Depth Interval ◽  
Depositional Processes ◽  
Secondary Formation ◽  
Exponential Decrease ◽  
Antarctic Snow ◽  
The Impact

Abstract. Snowpits along a traverse from coastal East Antarctica to the summit of the ice sheet (Dome Argus) are used to investigate the post-depositional processing of nitrate in snow. Seven snowpits from sites with accumulation rates between 24 and 172 kg m−2 a−1 were sampled to depths of 150 to 300 cm. At sites from the continental interior (low accumulation, < 55 m−2 a−1), nitrate mass fraction is generally > 200 ng g−1 in surface snow and decreases quickly with depth to < 50 ng g−1. Considerably increasing values of δ15N of nitrate are also observed (16–461 ‰ vs. air N2), particularly in the top 25 cm, which is consistent with predicted fractionation constants for the photolysis of nitrate. The δ18O of nitrate (17–84 ‰ vs. VSMOW), on the other hand, decreases with increasing δ15N, suggestive of secondary formation of nitrate in situ (following photolysis) with a low δ18O source. Previous studies have suggested that δ15N and δ18O of nitrate at deeper snow depths should be predictable based upon an exponential decrease derived near the surface. At deeper depths sampled in this study, however, the relationship between nitrate mass fraction and δ18O changes, with increasing δ18O of nitrate observed between 100–200 cm. Predicting the impact of post-depositional loss, and therefore changes in the isotopes with depth, is highly sensitive to the depth interval over which an exponential decrease is assumed. In the snowpits collected closer to the coast (accumulation > 91 kg m−2 a−1), there are no obvious trends detected with depth and instead seasonality in nitrate mass fraction and its isotopic composition is found. In comparison to the interior sites, the coastal pits are lower in δ15N (−15–71 ‰ vs. air N2) and higher in δ18O of nitrate (53–111 ‰ vs. VSMOW). The relationships found amongst mass fraction, δ15N, δ18O and Δ17O (Δ17O = δ17O − 0.52 × δ18O) of nitrate cannot be explained by local post-depositional processes, and are instead interpreted in the context of a primary atmospheric signal. Consistent with other Antarctic observational and modeling studies, the isotopic results are suggestive of an important influence of stratospheric chemistry on nitrate formation during the cold season and a mix of tropospheric sources and chemistry during the warm season. Overall, the findings in this study speak to the sensitivity of nitrate isotopic composition to post-depositional processing and highlight the strength of combined use of the nitrogen and oxygen isotopes for a mechanistic understanding of this processing.

scholarly journals Seasonal variation in the prevalence of profound hyponatremia (<125 mmol/l) in patients on admission to an acute hospital in Japan

2019 ◽  
Vol 28 (3) ◽  
pp. 211-213 ◽  
Author(s):  
Nobukazu Sasaki ◽  
Yuji Aoki
Keyword(s):  
Salt Intake ◽  
Medical Center ◽  
Relevant Literature ◽  
Warm Season ◽  
Cold Season ◽  
Acute Hospital ◽  
Drug Induced ◽  
Increased Risk ◽  
Significant Difference ◽  
The Impact

Hyponatremia is a common but important electrolyte disorder mostly complicated with other diseases. Recently, we experienced a case of a hypertensive patient in her seventies taking a thiazide diuretic, who presented with disorientation due to severe hyponatremia (serum sodium level, 104 mmol/l) on admission. Taking this opportunity, patients with profound hyponatremia (<125 mmol/l) on admission were investigated. Patients newly admitted to Matsumoto Medical Center (an acute hospital) were surveyed retrospectively for one year from May 1, 2016 to April 30, 2017. Patients with profound hyponatremia on admission were selected, and their clinical characteristics were evaluated. A total of 108 out of 4223 patients (2.6%; 67 men, 41 women) showed profound hyponatremia, and 101 out of 108 patients were 65 years old and over. The prevalence of profound hyponatremia in the warm season of April to October (3.1%, 76 in 2444 patients) was significantly ( p = 0.002, χ2 test) higher than that in the cold season of November to March (1.8%, 32 in 1779 patients). The monthly prevalence tended to correlate with the monthly average temperature of the local area ( r = 0.517, p = 0.085). There were six patients treated with thiazide diuretics in the warm season, while there were no such patients in the cold season, not reaching a significant difference ( p = 0.240). The present study demonstrated an increased risk of hyponatremia in elderly patients during the warm season. Considering also the relevant literature, health professionals should pay enough attention to thiazide- or drug-induced hyponatremia and the impact of water/salt intake for heat exposure.

scholarly journals How are oxygen budgets influenced by dissolved iron and growth of oxygenic phototrophs in an iron-rich spring system? Initial results from the Espan Spring in Fürth, Germany

2021 ◽  
Vol 18 (15) ◽  
pp. 4535-4548
Author(s):  
Inga Köhler ◽  
Raul E. Martinez ◽  
David Piatka ◽  
Achim J. Herrmann ◽  
Arianna Gallo ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Iron Oxidation ◽  
Warm Season ◽  
Cold Season ◽  
Oxygenic Photosynthesis ◽  
Dissolved Iron ◽  
Natural Iron ◽  
Spring System ◽  
Neutral Conditions ◽  
The Impact

Abstract. At present most knowledge on the impact of iron on 18O / 16O ratios (i.e. δ18O) of dissolved oxygen (DO) under circum-neutral conditions stems from experiments carried out under controlled laboratory conditions. These showed that iron oxidation leads to an increase in δ18ODO values. Here we present the first study on effects of elevated Fe(II) concentrations on the δ18ODO in a natural, iron-rich, circum-neutral watercourse. Our results show that iron oxidation was the major factor for rising dissolved oxygen isotope compositions in the first 85 m of the system in the cold season (February) and for the first 15 m during the warm season (May). Further along the course of the stream, the δ18ODO decreased towards values known for atmospheric equilibration around +24.6 ‰ during both seasons. Possible drivers for these changes may be reduced iron oxidation, increased atmospheric exchange and DO production by oxygenic phototrophic algae mats. In the cold season, the δ18ODO values stabilized around atmospheric equilibrium, whereas in the warm season stronger influences by oxygenic photosynthesis caused values down to +21.8 ‰. In the warm season from 145 m downstream of the spring, the δ18ODO increased again until it reached atmospheric equilibrium. This trend can be explained by respiratory consumption of DO combined with a relative decrease in photosynthetic activity and increasing atmospheric influences. Our study shows that dissolved Fe(II) can exert strong effects on the δ18ODO of a natural circum-neutral spring system even under constant supply of atmospheric O2. However, in the presence of active photosynthesis, with supply of O2 to the system, direct effects of Fe oxidation on the δ18ODO value become masked. Nonetheless, critical Fe(II) concentrations may indirectly control DO budgets by enhancing photosynthesis, particularly if cyanobacteria are involved.

scholarly journals How are oxygen budgets influenced by dissolved iron and growth of oxygenic phototrophs in an iron-rich spring system? Initial results from the Espan Spring in Fürth, Germany

2021 ◽  
Author(s):  
Inga Köhler ◽  
Raul E. Martinez ◽  
David Piatka ◽  
Achim J. Herrmann ◽  
Arianna Gallo ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Iron Oxidation ◽  
Warm Season ◽  
Cold Season ◽  
Oxygenic Photosynthesis ◽  
Small Stream ◽  
Natural Iron ◽  
Spring System ◽  
Neutral Conditions ◽  
The Impact

Abstract. At present most knowledge on the impact of iron on 18O / 16O ratios (i.e. δ18O) of dissolved oxygen (DO) under circum-neutral conditions stems from experiments carried out under controlled laboratory conditions. These showed that iron oxidation leads to an increase in δ18ODO values. Here we present the first study on effects of elevated Fe(II) concentrations on the δ18ODO in a natural, iron-rich circum-neutral watercourse. Our results show that iron oxidation was the major factor dominating the oxygen isotopes in the first 85 meters of the system in the cold season (December/February) and for the first 15 meters during the warm season (May). This trend existed despite a constant oxygen supply from the atmosphere. Further along the course of a spring and associated small stream system, the δ18ODO decreased towards values known for atmospheric equilibration. This may be due to reduced iron oxidation, increased atmospheric exchange and photosynthetic DO production. The presence of oxygenic phototrophic mats suggested their involvement in the observed decrease in δ18ODO values. In the cold season, the δ18ODO values stabilized around atmospheric equilibrium at +24.6 ‰, whereas in the warm season values decreased to +21.8 ‰. This suggests stronger influences by oxygenic photosynthesis. About 145 meters downstream of the spring, the δ18ODO increased again in the warm season until it reached the atmos-pheric equilibrium value of +24.6 ‰. This trend can be explained by a respiratory consumption of DO combined with a decrease in photosynthetic activity. Our study shows that dissolved Fe(II) can exert strong effects on the δ18ODO of a natural circum-neutral spring system even though a constant supply of atmospheric oxygen occurs. In the presence of active photosynthesis, with active supply of oxygen to the system, direct effects of Fe oxidation on the δ18ODO value becomes masked. However, critical Fe(II) concentrations may indirectly control DO budgets by enhancing photosynthesis, particularly if cyanobacteria are involved.

scholarly journals Association between air pollution and case-specific mortality in north-eastern part of Poland. Case crossover study with 4,500,000 person-years of follow-up

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
L Kuzma ◽  
A Kurasz ◽  
E J Dabrowski ◽  
M Swieczkowski ◽  
S Dobrzycki ◽  
...  
Keyword(s):  
Air Pollution ◽  
Warm Season ◽  
Cold Season ◽  
Funding Sources ◽  
Case Crossover ◽  
North Eastern ◽  
The Impact ◽  
Related Mortality ◽  
Cvd Mortality

Abstract Background Recent studies have reported associations between air pollution and daily mortality. The majority of them are conducted in highly polluted areas. Taking into consideration the scarce number of surveys from cities with moderate air quality we decided to conduct a study in this type of region. Purpose To assess the short-term impact of air pollution on cardiovascular (CVD), coronary artery-related (CAD), and cerebrovascular-related (CbVD) mortality. Methods The analysis with almost 4,500,000 person-years of follow-up with a time-stratified case-crossover design was performed. Results are reported as odds ratio (OR) associated with an increase in interquartile range (IQR). Results The analysed region was inhabited by almost 500,000 residents. From 2008 to 2017 in Bialystok, Lomza, and Suwalki we recorded 49,573 deaths – 34,005, 8,082, 7,486, respectively. The median daily concentrations of PM10 (23.8 μg/m3, IQR=16.9) was the highest in Lomza, Median daily concentration of PM2.5 was the highest in Bialystok (16.2 μg/m3, IQR=15.9). In the case of Suwalki, daily median PM2.5 concentration was 9.8 μg/m3 (IQR=8.7), and PM10 – 18.0 μg/m3 (IQR=14.3). The IQR increase in PM2.5 (OR 1.036, 95% CI 1.016–1.056, P&lt;0.001) and PM10 concentration (OR 1.034, 95% CI 1.015–1.053, P&lt;0.001) was associated with increased CVD mortality on lag 0 and this effect persisted on following days. The effects of PMs were more expressed in association with CAD-related mortality (OR for PM2.5 = 1.045, 95% CI 1.012–1.080, P=0.008), (OR for PM10 = 1.044, 95% CI 1.010–1.078, P=0.011) and CbVD mortality (OR for PM2.5 = 1.046, 95% CI 1.013–1.080, P=0.006), (OR=1.041 for PM10, 95% CI 1.002–1.082, P=0.038). Additionally, IQR increase in NO2 concentration was associated with increased CAD-related mortality at lag 0–1 (OR=1.055, 95% CI 1.004–1.108, P=0.032). The highest OR for PMs was noted in Suwalki compared to Bialystok and Lomza. The trend was noted regardless of the cause of death from lag 0 to lag 0–3. In a comparison of seasons, we noted higher CVD mortality OR in the cold season for PM10 in Suwalki (P=0.047) and Bialystok (p=0.001). However, the impact of NO2 (P=0.02) and PM10 (P=0.03) on CAD related mortality was higher in the warm season. Conclusions The impact of air pollution on CVD mortality is also observed in moderately polluted areas. PMs and NO2 had the greatest impact on CAD-related mortality. Differences in effect size and seasonality may depend on the source of air pollution. FUNDunding Acknowledgement Type of funding sources: None.

scholarly journals Mechanisms of Tropical Atlantic SST Influence on North American Precipitation Variability*

2010 ◽  
Vol 23 (21) ◽  
pp. 5610-5628 ◽  
Author(s):  
Yochanan Kushnir ◽  
Richard Seager ◽  
Mingfang Ting ◽  
Naomi Naik ◽  
Jennifer Nakamura
Keyword(s):  
North Atlantic ◽  
North American ◽  
General Circulation ◽  
Warm Season ◽  
Circulation Model ◽  
Cold Season ◽  
Tropical Atlantic ◽  
The North ◽  
Sst Variability ◽  
The Impact

Abstract The dynamical mechanisms associated with the impact of year-to-year variability in tropical North Atlantic (TNA) sea surface temperatures (SSTs) on North American precipitation, during the cold and warm halves of the hydrological year (October–September) are examined. Observations indicate that during both seasons warmer-than-normal TNA SSTs are associated with a reduction of precipitation over North America, mainly west of ∼90°W, and that the effect can be up to 30% of the year-to-year seasonal precipitation RMS variability. This finding confirms earlier studies with observations and models. During the cold season (October–March) the North American precipitation variability associated with TNA fluctuations is considerably weaker than its association with ENSO. During the warm season (April–September), however, the Atlantic influence, per one standard deviation of SST anomalies, is larger than that of ENSO. The observed association between TNA SST anomalies and global and North American precipitation and sea level pressure variability is compared with that found in the output of an atmospheric general circulation model (AGCM) forced with observed SST variability, both globally and in the tropical Atlantic alone. The similarity between model output and observations suggests that TNA SST variability is causal. The mechanisms of the “upstream” influence of the Atlantic on North American precipitation are seasonally dependent. In the warm season, warmer-than-normal TNA SSTs induce a local increase in atmospheric convection. This leads to a weakening of the North Atlantic subtropical anticyclone and a reduction in precipitation over the United States and northern Mexico, associated with the anomalous southward flow there. In the cold season, a response similar to the warm season over the subtropical Atlantic is identified, but there is also a concomitant suppression of convection over the equatorial Pacific, which leads to a weakening of the Aleutian low and subsidence over western North America, similar to the impact of La Niña although weaker in amplitude. The impact of TNA SST on tropical convection and the extratropical circulation is examined by a set of idealized experiments with a linear general circulation model forced with the tropical heating field derived from the full AGCM.

scholarly journals Air Quality in Windsor (Canada) and Impact of Regional Scale Transport

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1300
Author(s):  
Tianchu Zhang ◽  
Yangfan Chen ◽  
Rongtai Tan ◽  
Xiaohong Xu
Keyword(s):  
Air Quality ◽  
Regional Scale ◽  
Warm Season ◽  
Cold Season ◽  
Control Measures ◽  
Effective Control ◽  
Risk Level ◽  
Small Contribution ◽  
Air Masses ◽  
The Impact

Air Quality Health Index (AQHI) is a scale designed in Canada to help residences understand the impact of air quality on health. This study investigated temporal variability of daily AQHI and impact of regional transport on AQHI in Windsor, Ontario, Canada from 2016 to 2019. The four-year average daily AQHI was 2.9, slightly below the upper limit of the low health risk level of 3. AQHI value decreased from 2.95 to 2.81 during the study period, indicating the improvement of air quality. Half of the days, AQHI were 3 regardless of season. AQHI was higher in the warm season (3.1) than in the cold season (2.6) due to more frequent moderate risk days (27%, AQHI = 4) in warm season and more frequent low risk days (42%, AQHI = 2) in the cold season. Among the three pollutants considered, O3 was the most frequently reported dominant contributor to daily AQHI (88% of days), followed by NO2 (12%), especially in the cold season, with small contribution from PM2.5 (<1%). Trajectory analysis found that AQHI ≤ 3 days were closely associated with air masses from the north and northwest, whereas AQHI > 3 days were closely associated with air masses from the west and southwest. This is because northerly flows brought in clear air mass owing to less industrial facilities. Polluted air masses were transported from the south of Windsor, where several industrial states of the US were located. Directional AQHI resembles O3 more than NO2 or PM2.5 concentrations do. Further improvement of AQHI in Windsor could be challenging because O3 concentrations have continued to increase in recent years. Thus, more effective control measures to mitigate O3 pollution are warranted to reduce its impact on human health and the environment.

A Predictive Model of the Impact of the Skidding System on Forest Soil in Severe Climatic Conditions

2020 ◽  
pp. 131-144
Author(s):  
S.E. Rudov ◽  
◽  
V.Ya. Shapiro ◽  
O.I. Grigoreva ◽  
I.V. Grigorev ◽  
...  
Keyword(s):  
Forest Soil ◽  
Warm Season ◽  
Climatic Conditions ◽  
Soil Freezing ◽  
Class Iii ◽  
Freezing And Thawing ◽  
Metal Structures ◽  
Rapid Adjustment ◽  
Soil Freezing And Thawing ◽  
The Impact

In the Russian Federation logging operations are traditionally carried out in winter. This is due to the predominance of areas with swamped and water-logged (class III and IV) soils in the forest fund, where work of forestry equipment is difficult, and sometimes impossible in the warm season. The work of logging companies in the forests of the cryolithozone, characterized by a sharply continental climate, with severe frosts in winter, is hampered by the fact that forest machines are not recommended to operate at temperatures below –40 °C due to the high probability of breaking of metal structures and hydraulic system. At the same time, in the warm season, most of the cutting areas on cryosolic soils become difficult to pass for heavy forest machines. It turns out that the convenient period for logging in the forests of the cryolithozone is quite small. This results in the need of work in the so-called off-season period, when the air temperature becomes positive, and the thawing processes of the soil top layer begin. The same applies to the logging companies not operating in the conditions of cryosolic soils, for instance, in the Leningrad, Novgorod, Pskov, Vologda regions, etc. The observed climate warming has led to a significant reduction in the sustained period of winter logging. Frequent temperature transitions around 0 °C in winter, autumn and spring necessitate to work during the off-season too, while cutting areas thaw. In bad seasonal and climatic conditions, which primarily include off-season periods in general and permafrost in particular, it is very difficult to take into account in mathematical models features of soil freezing and thawing and their effect on the destruction nature. The article shows that the development of long-term predictive models of indicators of cyclic interaction between the skidding system and forest soil in adverse climatic conditions of off-season logging operations in order to improve their reliability requires rapid adjustment of the calculated parameters based on the actual experimental data at a given step of the cycles.

scholarly journals Impact of Air Infiltration on IAQ and Ventilation Efficiency in Higher Educational Classrooms in Spain

2021 ◽  
Vol 13 (12) ◽  
pp. 6875
Author(s):  
Irene Poza-Casado ◽  
Raquel Gil-Valverde ◽  
Alberto Meiss ◽  
Miguel Ángel Padilla-Marcos
Keyword(s):  
Natural Ventilation ◽  
Well Being ◽  
Cold Season ◽  
Climate Conditions ◽  
Air Infiltration ◽  
Ventilation Efficiency ◽  
Educational Buildings ◽  
Set Up ◽  
Total Volatile Organic Compounds ◽  
The Impact

Indoor air quality (IAQ) in educational buildings is a key element of the students’ well-being and academic performance. Window-opening behavior and air infiltration, generally used as the sole ventilation sources in existing educational buildings, often lead to unhealthy levels of indoor pollutants and energy waste. This paper evaluates the conditions of natural ventilation in classrooms in order to study how climate conditions affect energy waste. For that purpose, the impact of the air infiltration both on the IAQ and on the efficiency of the ventilation was evaluated in two university classrooms with natural ventilation in the Continental area of Spain. The research methodology was based on site sensors to analyze IAQ parameters such as CO2, Total Volatile Organic Compounds (TVOC), Particulate Matter (PM), and other climate parameters for a week during the cold season. Airtightness was then assessed within the classrooms and the close built environment by means of pressurization tests, and infiltration rates were estimated. The obtained results were used to set up a Computational Fluid Dynamics (CFD) model to evaluate the age of the local air and the ventilation efficiency value. The results revealed that ventilation cannot rely only on air infiltration, and, therefore, specific controlled ventilation strategies should be implemented to improve IAQ and to avoid excessive energy loss.

scholarly journals Temperature and Relative Humidity Profile Retrieval from Fengyun-3D/HIRAS in the Arctic Region

2021 ◽  
Vol 13 (10) ◽  
pp. 1884
Author(s):  
Jingjing Hu ◽  
Yansong Bao ◽  
Jian Liu ◽  
Hui Liu ◽  
George P. Petropoulos ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Real Time ◽  
Wide Spectrum ◽  
Warm Season ◽  
Arctic Region ◽  
Cold Season ◽  
The Arctic ◽  
Practical Applications ◽  
A New Technique ◽  
The Arctic Region

The acquisition of real-time temperature and relative humidity (RH) profiles in the Arctic is of great significance for the study of the Arctic’s climate and Arctic scientific research. However, the operational algorithm of Fengyun-3D only takes into account areas within 60°N, the innovation of this work is that a new technique based on Neural Network (NN) algorithm was proposed, which can retrieve these parameters in real time from the Fengyun-3D Hyperspectral Infrared Radiation Atmospheric Sounding (HIRAS) observations in the Arctic region. Considering the difficulty of obtaining a large amount of actual observation (such as radiosonde) in the Arctic region, collocated ERA5 data from European Centre for Medium-Range Weather Forecasts (ECMWF) and HIRAS observations were used to train the neural networks (NNs). Brightness temperature and training targets were classified using two variables: season (warm season and cold season) and surface type (ocean and land). NNs-based retrievals were compared with ERA5 data and radiosonde observations (RAOBs) independent of the NN training sets. Results showed that (1) the NNs retrievals accuracy is generally higher on warm season and ocean; (2) the root-mean-square error (RMSE) of retrieved profiles is generally slightly higher in the RAOB comparisons than in the ERA5 comparisons, but the variation trend of errors with height is consistent; (3) the retrieved profiles by the NN method are closer to ERA5, comparing with the AIRS products. All the results demonstrated the potential value in time and space of NN algorithm in retrieving temperature and relative humidity profiles of the Arctic region from HIRAS observations under clear-sky conditions. As such, the proposed NN algorithm provides a valuable pathway for retrieving reliably temperature and RH profiles from HIRAS observations in the Arctic region, providing information of practical value in a wide spectrum of practical applications and research investigations alike.All in all, our work has important implications in broadening Fengyun-3D’s operational implementation range from within 60°N to the Arctic region.

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