Environmental Risk Analysis of Different Segments of The Arctic Northeast Route

: There are huge differences in the sea ice conditions, climate and environment, geographical conditions and communication conditions in the Arctic waters, and the equipment and navigation requirements of ships are also different. In order to ensure the safety and success of the ships, through the route, this paper using fuzzy level analysis (Fuzzy Analytic Hierarchy Process, FAHP), build the northeast arctic route risk evaluation index system, targeted analysis of different segments, the results show that: (1) although the sea risk point is different but the natural environment risk has a significant impact on the arctic waters.(2) The risk coefficient of Arctic route is higher than that of traditional ordinary routes. Among the five sea areas in this study, Chukchi Sea is the highest, followed by East Belia Sea. The crew need to pay more attention when sailing.(3) The research in this paper can provide a reference for the navigation safety of the northeast Arctic shipping route.


Introduction
Global warming and the melting of sea ice are providing more opportunities for the development of international shipping and enhancing global attention to the Arctic routes.However, the harsh natural conditions, poor shipping infrastructure, and scarcity of ports along the Arctic routes currently exacerbate the risks of navigation.Therefore, a comprehensive and systematic analysis of the navigational environment of different segments of the Arctic Northeast Passage, and the identification of its risk factors, are of great importance for the safety of Arctic navigation.
Foreign scholars have conducted extensive research on the navigational environment of the Arctic routes, covering aspects such as channels, climate, ice conditions, and ships.As the importance of the Arctic region has become increasingly prominent, related research has also been further developed and improved.Li, ZF used the grey fuzzy comprehensive evaluation method to assess the navigational environment of the Arctic routes, concluding that hydrological factors, navigational aids, and information factors are the most crucial elements affecting the navigational environment of the Arctic routes, providing a reference for smooth navigation in the Arctic.Bi, WL, and others employed the Analytic Hierarchy Process to establish a navigational model for the Arctic routes, determining the weights of various indicators and concluding that the Arctic is unsafe but navigable.Wen-Hwa, Shyu used the fuzzy AHP based on the AHP expert questionnaire to analyze respondents' opinions, exploring their attitudes towards the construction of the Arctic routes.The results showed that "safety and risk" are the most significant aspects affecting the construction of the Arctic routes.Although China's research on the Arctic started relatively late, influenced by the Ice Silk Road, Chinese scholars have gradually increased their research on the Arctic region in the past decade.Domestic scholars' research is mainly focused on navigational feasibility, navigational environment analysis, and geopolitics.Li, Zhenfu evaluated the geopolitical security index of the Arctic routes from a geopolitical perspective, concluding that it is at a "third-level" standard.Ma, Xiaoxue evaluated the safety level of the Arctic routes based on resilience theory and used the Bayesian network method for quantitative assessment, further enhancing the safety and success of Arctic navigation.Cao, Yunfeng started from the rapid melting of sea ice, researching the changing pattern of navigational capacity of various Arctic routes in recent years, concluding that the navigational potential of the Arctic routes is continuously increasing.Li, Fengpeng focused on the Arctic navigational environment and, using a comprehensive evaluation method, assessed the navigational risks of the Arctic routes, concluding that the main risk factors affecting the navigation of ships in the Northeast Passage, in descending order, are the density of sea ice, temperature, and visibility, providing a reference for the navigation of the Arctic routes.As can be seen, both domestic and foreign scholars' analyses of the safety factors of the Arctic routes are more focused on exploring the safe navigation of the Arctic routes from a risk perspective.
The research of the aforementioned scholars provides important theoretical support for the safety of navigation on the Arctic routes.However, the analysis of the aforementioned studies shows that current academic research on the safety of the Arctic routes mostly starts from its entirety, lacking an analysis of the differences in risk between different segments.Compared to other routes, the Arctic routes are quite special, and a thorough analysis of the navigational environment of the Arctic routes is necessary.Therefore, it is necessary to analyze the navigational environment of different segments of the Northeast Passage from the perspective of conditional differences, study the impact of various risk factors on the safe navigation of ships, and conduct a comparative analysis.By analyzing the risks of different segments, it is possible to predict which route is safer, which risk factors of the chosen route are the most important factors affecting the safe navigation of ships, and allow shipping companies and crews to take safer protective measures.
This paper builds a risk assessment index system based on the safety risk characteristics of different segments of the Arctic Northeast Passage, attempting to identify several risk factors affecting the navigational environment of the Arctic Northeast Passage and establish an evaluation index system.The Fuzzy Analytic Hierarchy Process (FAHP) and fuzzy comprehensive evaluation are used to assess the risks of different routes in the Arctic Northeast region, establishing a risk assessment model for different segments of the Arctic Northeast Passage, and ultimately measuring the risk levels of each segment.On this basis, it provides a decision-making reference for the safe navigation of the Northeast Passage.

Risk Analysis of the Arctic Northeast Passage by Segment
Navigational risk refers to the potential dangers and disasters that may occur during the navigation of ships.This paper summarizes the main factors of navigational risks of the Arctic Northeast Passage as natural environmental risks, geopolitical risks, dynamic navigational aids, and static navigational aids.Detailed analysis is shown in Figure 1.

Figure 1. Fishbone chart of factors affecting navigation risk of Northeast Arctic route
The natural environment is a crucial factor affecting the navigation of the Arctic Northeast Passage, with the following main impacts: currents (ocean currents), sea ice, wind, temperature, visibility, channel depth, and the distribution of major ports.The natural environment of the Arctic Northeast Passage has a significant impact on both shipping safety and economic efficiency.It necessitates the reliance on high-tech means for ships and navigation equipment to strengthen monitoring, forecasting, and response measures to ensure the smooth and safe navigation of the route, as shown in Table 1, Table 2 and Table 3.
(1) Analysis of Natural Environmental Risk Factors

Ocean current
The ocean currents around the Arctic consist of two main systems: the coastal gyre and the oceanic circulation.Coastal currents are significantly influenced by sea ice and land topography, while oceanic currents are influenced by global ocean circulation, playing an essential role in the climate and ecological environment of the Arctic region.

Sea ice
Sea ice is the most significant natural environmental factor affecting the navigability of the Arctic routes.When the sea ice is thick, it increases the resistance and friction for ships traveling through the ice, reducing the speed and efficiency of the vessels.When the sea ice is dense, it makes the ice harder to break or penetrate, increasing the risks and difficulties of navigation.Therefore, in Arctic navigation, it's crucial to adjust the ship's route and speed timely according to the thickness and density of the sea ice to ensure safe and smooth navigation.

The wind
The Arctic region is highly susceptible to weather changes due to its climate, so wind speeds often change rapidly.The Northeast Arctic waters often experience unique meteorological phenomena such as blizzards and uneven distribution of day and night time in winter, intensifying the variability of wind speed in the region.The high wind speeds generate correspondingly large waves, posing significant challenges to maritime transport, fishing, and seabed oil and gas exploration.

Temperature
Temperature is one of the important factors affecting the navigational environment of the Arctic Northeast Passage.High temperatures can lead to more storms and meteorological disasters in the Arctic region, increasing the risks of ship navigation at sea.Low temperatures causing ice layer thickening and expansion of ice-covered areas can affect ship maneuvering and crew living conditions.

Visibility
Visibility in the Northeast Arctic waters is affected by ice and snow coverage.Fog is a primary factor causing low visibility in Arctic waters.

Mean water depth
The average water depth of the Northeast Arctic waters plays an important role in the navigability of the Arctic Northeast Passage.If the average water depth in the Northeast Arctic waters is shallow, the difficulty of navigation will significantly increase, requiring more precise route planning and higher-tech ships to pass through.Additionally, the shallow water depth can also affect the ship's speed, leading to decreased transportation efficiency.

Supply port along the line
Supply ports along the Arctic include ports, islands, and cities located along the Arctic coast.Major supply ports include Murmansk, Dixon, Tiksi, Pevek, and Provideniya.It should be noted that these coastal ports face harsh weather and sea conditions throughout the year.Investments are required to continually improve and upgrade port infrastructure and equipment to ensure support, security, and services for various activities in the Arctic region.
(2) Analysis of Geopolitical Environmental Risk Characteristics

Minefields left over from war
During World War II, the Arctic Northeast Passage was an important route used by the Soviet Union for transporting materials and troops.Many ships from warring nations were sunk in this area, resulting in a large number of unexploded war remnants, such as mines, in the region.These unexploded ordnance and naval mines not only pose a threat to the safety of the shipping lanes in the area but can also impact the ecology and environment of the region.With the reduction of Arctic sea ice, the time these unexploded ordnance are covered by ice is decreasing, further intensifying the safety risks in the area.

Disputes over sovereignty
In terms of war remnant minefields, the Barents Sea is an important shipping area and was also a significant battleground for naval battles between the Soviet Union and Germany during World War II.
Over time, a large number of unexploded bombs, shells, mines, and other war remnants have accumulated in the waters of the Barents Sea, forming war remnant minefields.These pose significant risks to activities such as ship anchoring and oil and gas exploration in the sea.The Chukchi Sea was also one of the battlegrounds where the Soviet Union and Germany conducted naval battles during World War II.In this area, a large number of unexploded shells, bombs, and other war remnants have accumulated, forming war remnant minefields.
(3) Analysis of the Completeness of Dynamic Navigational Aids

Timeliness of arrival of rescue ships
The timeliness of the arrival of rescue ships refers to the period during which the action of rescue ships is valuable in the event of a maritime emergency, and this period of time is inversely proportional to the effectiveness of the response.The speed of the rescue directly impacts the timeliness of the rescue ships.In this paper, the overall distance is calculated based on the distances between the two ends of each sea area.Using the MarineTraffic software for measurement and statistics, the approximate distance for each sea area can be obtained, as shown in Figure 2.
Weather and sea state forecast Weather and sea condition forecasts are based on meteorological conditions and changes in the marine environment to predict the weather and sea conditions of a certain sea area for a future period.Weather and sea condition forecasts in the Arctic region are primarily conducted through various remote sensing technologies, marine observation equipment, and numerical models.Among these five sea areas, the Barents Sea has the best meteorological and hydrological environment nearby, which is most conducive to the conduct of rescue activities.The Kara Sea has the worst meteorological and hydrological environment.

Figure 2. Distance Map of the 5 Major Arctic Northeast Seas
Based on the statistics of the "NSR" transits reported by the China National Oceanic Administration (https://arcticlio.com/)from 2012 to 2020, arc4 ice-class ships have the highest frequency of transits through the NEP; therefore, Arc 4 is taken as the object of study.According to the document, the cruising speed of ARC4 is 22 knots.Therefore, the timeliness of rescue ships reaching each sea area can be roughly calculated based on time = distance ÷ speed, as shown in Table 4 and Table 5.The lack of infrastructure and high operating costs lead to insufficient search and rescue capabilities, making it difficult to conduct personnel rescues and resulting in less investment in rescue personnel.
Typically, the SAR device type is available The search and rescue equipment types for the Arctic Northeast Passage include, but are not limited to: satellite communication devices, radar and sonar equipment, search and rescue aircraft and helicopters, lifeboats and life rafts, cold-weather clothing, and warming equipment.

Emergency communications support conditions
Communication equipment performance along the entire Northeast Passage is poor, with no signal reception for devices other than Iridium phones above 75°N latitude.

Regional magnetic difference
Near the Magnetic North Pole, the magnetic variation changes rapidly with geographical location, significantly impacting navigation.The Kara Sea is affected by magnetic storms, experiencing about ten days per month with a magnetic variation of 4°.In the Laptev Sea, severe magnetic storms occur no more than 4-5 days per month, but the number of days with a magnetic variation reaching 4° can also be about ten days.In the East Siberian Sea, the number of days with a magnetic variation of 4° can reach 10-12 days.

Accuracy of chart scale
Due to the remote geographical location and harsh climate of the region, there has been a long-term lack of support from ships and shore station data.Therefore, the update of nautical charts for this region lags behind, and the accuracy of the nautical charts is relatively low.

Quantification of Indicator Weights
The Analytic Hierarchy Process (AHP) is a multi-factor decision analysis method that transforms decision-making problems into hierarchical structures.Through quantitative and qualitative methods and expert opinions, the problems are analyzed and resolved to reach the optimal decision-making solution.This paper first divides the impact degree of fuzzy evaluation corresponding to the indicator into 5 levels, namely, very low safety (VL), low safety (L), medium safety (M), high risk, and very high risk (VH).By calculating, a risk degree evaluation set is formed, as shown in Table 6 and Table 7.
In quantifying the weights of the indicators, for each level, the importance of each indicator is determined.The trapezoidal fuzzy numbers of Gupta et al. are used to judge the impact degree of the main dimensions, objectives, and indicators of the judgment layer to form a judgment matrix, thereby determining the weights of each indicator.The trapezoidal fuzzy number is represented as A(a1, a2, a3, a4), and the 5 levels of impact degree correspond to 5 trapezoidal fuzzy numbers, as shown in Table 8 and Table 9.

Indicator Weight Measurement
Through the Fuzzy Analytic Hierarchy Process (FAHP), the weights of the indicators are determined.Assuming there are n sea areas, the risk degree of the mth sea area is m m 1 2 n E  ( ， ，， ) , determined according to the trapezoidal fuzzy number corresponding to its risk degree scale, and the fuzzy evaluation set is m a a a a E ( ， ， ， ) .The specific process is shown below.
(1) Measure the binary consistency between evaluations of different sea areas in the Arctic Northeast Passage.

 
4 (2) Measure the average consistency of each sea area's evaluation.If the average consistency of the uth expert's evaluation is   u AA E , then its calculation formula is: (4) Consistency coefficient test: Test the consistency coefficient of the feature vector to ensure the credibility of the assessment results.

 
  (1 ) ( ) (5) Measure the cluster fuzzy number of the sea area's evaluation under this indicator.
a a a a a a a a a a (7) Normalize the results.

Fuzzy Synthesis
Fuzzy synthesis is a decision-making method that integrates multiple indicators, factors, or evaluation systems through mathematical model processing of various information.It is suitable for decision-making problems with many indicators, where the interactions and connections between indicators are complex and difficult to describe with precise numerical values.The fuzzy synthesis method adopts the idea of fuzzy mathematics and can effectively consider the impact of various factors, improving the scientific nature and accuracy of decision-making.
(1) Establish the evaluation model: In this paper, different rows in R reflect the membership degree of the five major sea areas based on different single indicators to the fuzzy subsets of each level.The fuzzy weight vector A is used to synthesize different rows, obtaining the overall membership degree of the evaluated sea area to the fuzzy subsets of each level, i.e., the fuzzy comprehensive evaluation result vector.Introduce a fuzzy subset B on V, called the fuzzy evaluation set, also known as the decision set.B( bn)  b1，b2，b3，

Evaluation of Influencing Factors
Based on statistical and measurement results, and referring to (1)~( 7), the binary consistency, average consistency, relative consistency, consistency coefficient, cluster fuzzy number are sequentially calculated, and then defuzzification is performed to obtain the defuzzified weight, normalized weight, and integrated weight of the indicators.The measurement results are shown in Table 10.
Based on the risk evaluation results, the following analysis is made: Among the five major sea areas, the Chukchi Sea poses the highest navigational risk, followed by the East Siberian Sea.The Barents Sea, Kara Sea, and Laptev Sea have relatively lower navigational risks.For the five major sea areas, natural environmental factors have the most significant impact.Among them, sea ice, visibility, average water depth, and the number of major ports pose higher risks.In terms of geopolitical environmental risks, the Barents Sea and Chukchi Sea segments have higher risks.The completeness of dynamic and static navigational aids has a relatively smaller impact on the navigational risks of the five major sea areas, as shown in Figure 3.

Conclusion
The geographical environment of the Arctic region is complex.This paper analyzes and evaluates the navigational environment of the five major segments of the Arctic Northeast Passage, using methods such as Analytic Hierarchy Process and fault tree analysis to quantify its risk points and make a relatively objective evaluation of the results, thereby determining the risk levels of different segments.
Based on the specificity, differences, and complexity of the natural environmental conditions of the five major segments of the Northeast Passage and human intervention, extensive basic data for each segment are collected, indicators are quantified, an indicator evaluation system is constructed around risk causes, and a fuzzy analytic hierarchy model is used to determine the weight of indicators, ensuring the objectivity and credibility of the importance of indicators.This provides important navigational tips and references for polar sailors before heading to different waters.
The results of the Northeast Passage indicator weights determined by the fuzzy resolution model show that ocean currents, sea ice density, sea ice thickness, visibility, and the number of major ports are the five most important risk factors affecting the navigation risks of the Northeast Passage.The research results place greater emphasis on the attention and investment in the safe navigation of polar sailors, which significantly compensates for the uncertainty caused by excessive reliance on subjective judgment in the study.
Affected by temperature , compared to traditional routes, navigation in the Arctic Northeast is usually risky.This proves that risk identification for using the Northeast route is very necessary, and this result provides an important reference for polar sailors navigating in the Arctic.
In conclusion, the analysis and evaluation of the navigational environment of different segments of the Arctic Northeast Passage are very complex and require considering multiple factors.Ships should be equipped and respond specifically for different segments.The analysis in this paper can provide a scientific reference for the navigational safety of ships on this route.

( 2 )Figure 3 .
Figure 3. Risk Analysis of the Navigational Environment of Different Segments of the Arctic Northeast Passage

Table 1 .
Natural Environmental Risk Factors

Table 2 .
Geopolitical Environmental Risk Factors

Table 3 .
Dynamic Navigational Equipment

Table 4 .
Timeliness of Rescue Ship Arrival

Table 5 .
Static Navigational Equipment

Table 7 .
Data Sources for Bottom-Level Indicators of the Risk Assessment System for Arctic Northeast Passage Navigation

Table 9 .
Diagnostic Results of the Navigational Risk of the Northeast Passage

Table 10 .
Results of Indicator Weights