Why Arctic warfare must be conducted by nuclear submarines becomes evident as one examines the unique nature of the Arctic Ocean environment and the state of today’s technology for operating in that Ocean area. Significantly, only submarines can control the Arctic Ocean and only submarines can contest this control. Moreover, the U.S. Navy has no other warfare area so distinctly different from all other sea areas of the world. In fact, jungle warfare comes the closest to being like Arctic warfare — certainly much closer than Indian Ocean warfare or Mediterranean Sea warfare.
There are subtle similarities between the Arctic Ocean and the jungle. Both have markedly different characteristics which are little understood by the average military man. In fact, one has to have been in these environments to appreciate their uniqueness, and both contain many unknowns. They have a similar remoteness and are not fully explored, while providing harsh impacts on military forces operating within their environments.
So, with an image of the arctic as a jungle of the north, where cold water replaces the warmth and humidity of the jungle, where ice and snow replace the rocks, thickets and lush green trees, and where the unexpected is to be expected -let’s focus on why Arctic submarine warfare needs to be better understood.
The very things which make the Arctic Ocean different are the things which make it difficult to operate there. Specifically, they are the extreme cold, the ice cover and the remoteness. That the submarine navy has been in the Arctic for thirty years doesn’t promise that much is known about operating there. The Arctic Ocean is still essentially an unknown area for there remain significant gaps in our knowledge and understanding with respect to ice thickness, ice distribution, sea water density, ocean currents, ocean eddies and fronts, Arctic weather, and most importantly acoustic propagation under sea ice. When these shortcomings are combined with the fact that up until recently the U.S. Navy’s high latitude operations in the vicinity of sea ice were limited to an annual single-ship Arctic deployment — usually by a submarine – one can better recognize that our 30 year experience provides only a simple base with few refinements. The Arctic Ocean is not the same as the open ocean. Because of its unique character, solutions to operational problems in the Arctic are different than for open ocean warfare. To operate effectively in the Arctic, whether it is a submarine or an ASW aircraft, the platform must have better all-around attributes than its counterpart designed for more temperate climates. For one, it must be more robust. And it must have undergone far more research and development to meet such standards. In today’s warfare environments and with equipments designed for the open ocean, performing well in the Arctic — on the ice, under the ice, or in the airspace overhead, is less efficient than in the open ocean.
To properly define warfare in the Arctic, there is a need to examine what the Arctic environment sets as limits on the various warfighting elements of the Navy.
First, is it possible to penetrate the Arctic surface icebarrier, rapidly and repeatedly to allow use of operational systems? The actual answer to that question is “no.” The only assured way of successfully delivering a sensor system or weapon from one side of the ice barrier to the other is through an opening in the ice cover — such as an open lead or polynya. Actual penetration of the ice is a different matter
— it becomes a chance event or is impossible. There is an inability to measure the thickness of ice with sufficient accuracy, remotely and in real time, by any existing operational system. Current ice thickness measurement accuracies vary plus or minus 50%. Imagine ice estimated to be six feet thick
— the nominal maximum thickness of first year ice — which might be as much as nine feet in thickness or only three feet thick. H the thickness is on the high side, a sensor which must get through the ice may not be usable. To counter the potential error in measurement, ice penetration devices are thus required in great numbers — which do not exist. Thus, if Arctic ASW sensors must penetrate the ice to be effective with today’s technology, there is a high probability of failure in such an ASW system when employing such sensors. A platform cannot properly execute a warfare task in the Arctic if it doesn’t have an assured chance of breaching the ice barrier anytime it desires. Why the nuclear submarine is, at present, the only effective means for controlling the underseas of the Arctic can be shown by examining surface and air ASW systems in the Arctic environment. Importantly, it must be recognized that the Arctic Ocean is and will be used by strategic submarines for their patrols, as well as for transfers of ships, including submarines, through and across this Ocean.
Surface Ships
Surface warships cannot operate in the near vicinity of the ice edge or in the Marginal Ice Zone because no U.S. Navy surface warships are ice hardened. In times of darkness or in daylight with a surface cover of fog, radar or visual detection of floating sea ice is not assured at safe ranges because of the low profile which such ice presents. Thus, the threat to the seaworthiness of surface ships in this ice zone is great. Consider further that the floating sea ice can move as rapidly as two knots when set in motion by both wind and current, and worse, that as little as four knots of wind is sufficient to put pack ice and free floating ice into motion. Thus, during a dark winter night — or eighteen hours of poor visibility — the ice edge with its threat to a surface ship, can move 36 nautical miles, the width of one convergence zone. Showing proper respect for this hazard reduces a surface ship’s ASW effectiveness significantly as the vessel approaches the last reported position of the ice edge by closer than 50 miles. In fact, when one considers the lack of real time information about the ice edge, and the lack of knowledge of local winds and currents in the marginal ice zone, it is prudent for surface ships to stay at least 100 nm from the ice edge. Getting any closer merely courts disaster.
At the same time, because of the difficulty of distinguishing submarines from large ice rubble, surface warship capability is badly degraded.
Use of an air cushion vehicle (ACV) over the ice, is at first glance attractive. (With a V -22 Osprey tiltrotor aircraft aboard, the combined ASW system might seem even more attractive.) The use of ACVs alone seems to fit an ASW requirement for a medium-range, medium speed ASW platform and the ACV’s previous performance over an ice covering would contribute to that optimism. However, one must realize that the platform has never operated over sea ice and over nothing more than benign shore-fast ice — and that its maneuverability when on cushion is not readily compatible with abrupt surface irregularities; and that a long range highresolution navigation radar with pinpoint accuracy is a necessary first step in this capability. But, one can recognize that the existence of such a system is not near at hand. Perhaps, if the performance of the ACV over sea ice can be improved, its best role would be as a platform to insert ocean surveiJiance systems or act as an Arctic SURTASS-Iike platform where the response time inherent to ASW weapons delivery would be l,ess an issue. Additionally, the ASW system of an ACV carrying an Osprey would encounter the same limitations described below under “Aircraft.”
Aircraft
What about aviation in the Arctic? As with surface ships, air ASW warfare is severely hampered by the environment. An ice-penetrating sonobuoy is still not operational. However, because 60% — 3.3 million square miles — of the Arctic is under permanent sea ice that is up to 20 feet thick, the effectiveness of sonobuoys which are ice-penetrating would still be low because of the time required to penetrate the ice cover.
It is recognized that within the areas of permanent sea ice there exist small open water areas or thin ice leads and polynyas — even in mid winter. Deploying any sensor through thin ice or open water, however, requires an accuracy much akin to that achieved by a World War II bombardier. Otherwise, an ASW aircraft needs an accurate remote sensing system to measure and map ice thickness over large areas of permanent ice. Even then, the sensor mortality rate would be high — producing a great reduction in ASW effectiveness. Also, with daylight being essential to use of this technique, there’s so little daylight in the Arctic as to make this method undependable. Aircraft endurance also becomes a problem since there are few high latitude airfields from which ASW aircraft sorties can be conducted. If the aircraft must descend to a low altitude to deploy sensors with the accuracy needed, fuel consumption increases significantly and on-station time becomes critical. Conversely, if a sonobuoy barrier could actually be deployed at normal altitude, the loiter time onstation, waiting for ice-penetration of the sonobuoys, would further reduce profitable on-station time. Currently, thermal technology techniques provide ice penetration at a rate of one foot every five minutes. Thus, each sonobuoy would require upwards of 45 minutes to penetrate Arctic sea ice of nominal thickness — of about 8 feet. Can an aircraft wait that long on station? Of even greater concern is how an ASW aircraft can determine where it should deploy a sonobuoy pattern. The traditional cueing methodology used in the open ocean is not usable in the Arctic. Two things degrade the speed of delivery of Arctic Ocean surveillance information which ASW forces might expect. First, there are fewer available detections because of the ice cover and second there must be a reliance on polar orbiting satellites. Time late over ASW contacts will thus be greater in the Arctic as will the ensuing radius of uncertainty of any contact. The problem is great.
Significantly, the foregoing ASW capability assumes that ASW aircraft can freely occupy the sky over the high Arctic regions without drawing a reaction from the enemy. But the Soviets, for example, would have as easy a job of interdicting ASW aircraft as the U.S. would have of protecting them. Thus, in the face of an air threat based on a land mass that circles over one-third of the periphery of the Arctic Ocean, air ASW becomes potentially too hazardous.
Arctic Capable Weapons
The foregoing discussion has stressed the challenges of sensors breaching the ice barrier in support of a warfare task. Proper rapid delivery and performance of weapons, particularly for ASW, is another matter. At present, the torpedo launched from a submarine is the only weapon that can be used under the ice satisfactorily. No ice penetrating weapons exist today.
The effectiveness of air-to-underwater and surface-tounderwater weapons is generally untested. Extensive R&D is needed to achieve: (1) target discrimination by the weapon; (2) sufficient accuracy of platform sensors for localization for weapon use; (3) timeliness of offboard information; and ( 4) effective high latitude delivery tactics.
An additional challenge for ASW warfare is the adapting of deep ocean surveillance systems to the Arctic Ocean environment, recognizing that the accepted techniques of ocean surveillance using the deep sound channel are not going to be as effective under the ice as in the open oceans — even if it were economicaJiy and operationally feasible to install such systems today.
Other Sensors
Unfortunately, geosynchronous satellites have a coverage that only extends north to approximately 75° north latitude -less than 600 miles above the Arctic circle, and are not usable over any area within 900 nautical miles of the North Pole. Truly effective high latitude satellites must be in polar orbit. In a polar orbit, a satellite would have to be dedicated to Arctic military use. However, most satellites in a polar orbit are for environmental purposes such as ice distribution. Further, their capability lies in being able to map ice anomalies, but without sufficient resolution and timeliness for warfare purposes.
The Nuclear Submarine
Only nuclear submarines can operate effectively in the Arctic Ocean — and only nuclear submarines configured for the under-ice environment can operate safely there. The Arctic Ocean submarine must have ice-hardened sails, strengthened control surfaces and sonars which can: upward scan to recognize the irregularities of the under-surface of the ice cap; forward-look to spot deep ice keels (some of which project downward in excess of 50 feet); permit transit through narrow passages, (only Fram Strait to the east of Greenland provides a deep entrance to the Arctic Ocean). Additionally, nuclear submarines should have mine-locating devices because of the high probability of encountering submarine-laid mines in restricted and shallow waters of the Arctic Ocean.
Because of transit difficulties in moving to station in the Arctic Ocean, submarines operating there should necessarily be forward based to increase on-station time.
Significantly, submarine operations are not affected by the light of daylight or the darkness of night. Moreover, the underseas of the mid-Arctic Ocean is basically benign with low ambient noise except at the ice-cap edges. But it is afflicted with unpredictable densities due to variations in salinity, and currents which make vertical-surfacing through open leads or polynyas like trying to land against a moving pier.
With the very cold ice-cap making the temperature of the upper stratum of the ocean colder than the lower stratum, a positive sound velocity profile bends sound rays towards the surface, creating a near-surface sound duct which promises long sound-propagation ranges. But sound transmissions from submarines at the same time are scattered by the rough underside of the ice, reducing detection ranges, and may not provide the correct bearing of return echoes from an enemy submarine.
Within this environment, strategic submarines can use the undersurface of the ice cap to remain hidden from prowling enemy SSNs and can use open areas of the Arctic seas, or areas covered by thin ice, for discharge of their weapons. Also, submarines and surface ships in transit across the Arctic Ocean, while avoiding submarine-laid minefields, can, for much of their passage, defensively use the shallow waters of the Arctic Ocean.
Thus, it is only attack submarines — SSNs — which can control areas of the Arctic Ocean and only enemy SSNs which can contest that control.
Summary
Because of all the impediments to Arctic ASW execution, and because of system performance anomalies which must be overcome in the Arctic, only the submarine at the present time can successfully perform in the Arctic warfare role. Furthermore, the majority of near-term warfare improvements currently in development will support a better performance by the submarine in Arctic ASW.
In short, the submarine is the only platform capable of conducting warfare in the Arctic with any reliability. It is the only platform that can get there, stay there, respond to any kind of cueing, and deliver a weapon to kill.
George F. Newton
