The work was performed during the period October 1994 to September 1995 under the supervision of Mr. Paul Krause, Project Leader, Ms. Betty Mandel, Chief of the Environmental Sciences Division, and Mr. John V. E. Hansen, Director of the Remote Sensing Laboratory.
The final editing and production sequence was performed during the period November 1995 to February 1996 with the help of Mr. Michael McDonnell, Team Leader, Mr. Juan Perez, Chief of the Modeling and Simulation Division, and Mr. Richard Herrmann, Director of the Topographic Applications Laboratory.
Mr. Walter E. Boge was the Director, and COL Richard G. Johnson was Commander and Deputy Director of the U.S. Army Topographic Engineering Center at the time of publication of this report.
Once these parameters are known, it is up to the strategic and logistic planners to decide what type of weapons and support material will work best in the various world theaters. If a major political or military statement is deemed necessary, the timing of naval resupply becomes critical. As many as nine major tropical storms can be active at one time (as during 14 September 1967) thus significantly altering shipping routes and time enroute. It should be noted that the best time for an opposing force to strike would be at the time of landfall of a tropical storm in the area of interest. During such a window of opportunity, the cornerstone of our military posture (the electronics surveillance umbrella) is either at its weakest or nonexistent. This, in turn, maximizes their threat capability, particularly in a mountainous region such as the Korean Peninsula. As much as 31 inches of rain was recorded there in 24 hours. Other parts of Indochina have recorded as much as 131 inches of rain in 72 hours. To know the likely implications of an El Nino event in advance, as noted by the more than $10 billion in worldwide damages produced by the 1982-83 El Nino pattern, will allow strategic and logistical planners to be better prepared in their efforts to diffuse chaos in the world's political and military arenas of tomorrow.
As an El Nino event develops in the southwestern part of the North Pacific, the initial impression is not one of concern. There is little immediate economic, political, or strategic (military) value in these waters. But as the event continues to expand and unfold, immediate weather and short-term periodic climate changes can be felt from the United States (U.S.) to South America, from Europe to Africa, and from Asia to Australia. This report describes the general world impact of an El Nino event, and then sharpens the focus on the Korean Peninsula. In this region, El Nino causes negative economic impacts in agriculture - rice, in general, and the fishing industry, in particular, that could lead to strategic conflicts in an attempt to feed a hungry population. Thus, tactical decision aids for either strategic or humanitarian situations can be in error if existing climatic data summaries are used. If military planners are trying to establish either military maneuvers or the logistics of resupply, they will inevitably discover that El Nino's regional impacts are usually quite different from the stated climate data for a given area, thus impacting on the type of systems to be used and the all important "reaction time."
Even the absence of an El Nino event can be cause for alarm. The 10-year gap between moderate to strong El Nino's from 1943 to 1953 could easily be seen as the key factor in the strength of the Siberian High in the winter of 1950-51. With the proper data set warnings, it is quite possible that decisions for the tactical deployment of the 1st Marine Division and the type of equipment they fielded would have been radically altered for the infamous battle of "The Chosin Reservoir." With proper planning, having the 1st Marine Division, or any other division, fighting for 14 days in -30 ° F. temperatures against an enemy force of 120,000 should not happen again. Annual checks of the climate data sets should be considered by those in charge of tactical and logistical decision aids. One of the most important factors effecting climate data realism can be whether or not an El Nino mechanism is "on" or "off." Thus, these checks are necessary on an annual basis to ensure that short-term weather patterns that radically differ from the basic climatology for a given region are duly noted.
Early Spanish sailors who fished in small boats along the western-most shores of South America were familiar with the ocean currents of the region. Normally, the waters they fished were cold and flowed from south-to-north (Figure 1.) During certain years, the waters would reverse their flow and become very warm. This would usually begin to occur shortly after the Christian Christmas holiday. Thus, the sailors named the odd occurrence El Nino, meaning "the Christ Child." A change to the El Nino pattern can be seen in the June 1985 to June 1986 sea surface temperature data shown in Figure 2.
The worldwide effects of a strong ENSO are shown in the damage reports compiled from the 1982-83 event ( Table 1). Total damage reported worldwide exceeded $10 billion. A chronological sequence of these events gives another perspective of this far-reaching problem ( Table 2). Military planners should note that climate data used for either military or humanitarian exercises may be in a state of flux during an El Nino occurrence.
How powerful can an El Nino event be? A direct indication of this power and the resultant generation of heat in the Pacific Ocean during such an event can be provided by satellite sensors. Measurements by NASA's TOPEX/Poseidon satellite (a collaboration between the U. S. and France) of the 1994-95 El Nino shows that Pacific sea levels were elevated 6 inches over an area the size of the U. S. (more than 3 million square miles) by the end of 1994.
This two-dimensional picture was extended vertically to three dimensions by renowned meteorologist Jacob Bjerknes in 1969. He noted that in addition to the north-south circulation known as the Hadley Cell, trade winds across the tropical Pacific continued to flow from east-to-west. He theorized that to complete the loop, air must rise above the western Pacific, flow back east at high altitudes, then descend over the eastern Pacific.
Dr. Bjerknes called this the Walker Cell circulation (in honor of Sir Albert Walker, a renowned meteorologist of the last century). He also was the first to recognize that it was closely connected to the oceanic changes of El Nino (warming waters) and La Nina (colder waters) (Figure 5). Thus, when the effects of the SO are coupled with the periodic mechanisms that stop the natural equatorial upwelling (whether cold or warm), you have two types of Pacific basin water masses to analyze (Figure 6) .
The two primary considerations of military significance from an El Nino event are droughts and floods. With the U.S.'s strong emphasis on "electronic warfare and suppressive countermeasures," it should be noted that droughts produce great amounts of dust. During the 1982-83 El Nino event, the drought that enveloped eastern Australia ( Figure 7) produced a dust storm that dumped more than 11,000 tons of dry soil on the city of Melbourne in 40 minutes. This drought became the driest summer in the Melbourne area in more than 200 years.
The converse of this tactical and logistical problem is the flooding that occurred in northern Peru ( Figure 8) and Ecuador ( Figure 9). Note the normal precipitation patterns for South America in June (Figure 10). Peru recorded its greatest rainfall amounts in more than 200 years during the El Nino period of 1982-83. Guayaquil, Ecuador recorded 13 times its normal rainfall during the same time period. The El Nino related storms that produced these heavy rains also produced an almost continuous heavy surf that resulted in widespread coastal damage to Peru and Ecuador that exceeded $650 million. The heavy rains soaked hillsides and brought thousands of homes tumbling down in the mudslides. Thus, any plans for logistical resupply and relief would be severely curtailed as local roads become impassable. The flood-swollen rivers, such as the Piura in Peru (Figure 11), wiped out prime banana and rice growing regions, swept away vital bridges, and, flooded towns causing widespread unsanitary conditions that resulted in virulent diseases spreading throughout the area. The extent of these epidemic prone areas can be markedly changed by strong ENSO - El Nino (1982-83 warm), or the opposite effect of ENSO - La Nina (1988-89 cold) events that, in turn, influence the positioning of the average minimum temperature 10 ° C. isotherm (50 ° F.). Studies by Dr. Paul R. Epstein, Harvard Medical School, have shown that where this line develops becomes the boundary within which malaria and dengue fever epidemics are highly prone to start, and then expand with either poor or disrupted sanitation facilities (as in the example for Peru and Ecuador) (Reference 1).
These relatively recent events should act as a signal to planners and logistics experts that long-term action plans should be initiated. The cycle for these events can take up to 24 months to complete when involving moderate to strong El Ninos. It also should be noted that El Nino events that are very strong to extreme in their intensity can reduce the cycle time to as little as 12 to 18 months.
The ENSO events of the last 300 years have been charted with their relative strengths and intensities ( Figure 12 and Table 3). The event that is usually analyzed first is the 1982-83 El Nino, considered to be the strongest ENSO event to ever come under scientific scrutiny. The scientific community has shown that local effects off the coastline of Peru are actually linked to events in the central and western Pacific. It is now coming into focus that ENSO events, particularly the stronger ones, can affect conditions in the other two tropical basins (i.e. the Atlantic and the Indian Oceans) as well. Thus, the original "smoking gun" was the occasional loss of an anchovy harvest off the coast of Peru; however, the strategic implications for military planners, particularly in tropical waters, is immense.
This is a phenomenon of global proportions in terms of cause and effect. To further illustrate the plight of the local fishing industry, note the reverberations on the rest of the food chain. When food supplies should be most plentiful, an El Nino event diminishes them by reducing upwelling and the resultant primary food production. The magnitude of this problem can be better understood by the fact that more than 17 million birds populating the Christmas Islands disappeared for lack of food, which in turn, doomed their recently hatched nestlings. Albatross, cormorants, penguins, and marine iguanas are other species that are adversely affected by the lack of food. A compounding problem with El Nino events is the timing of the mechanisms. The warmest sea surface temperatures and their impacts occur when many species, mammals in particular, are breeding. This loss of food has particularly negative effects on either expectant females or their young. It has been reported that nearly 100 percent of the fur seal pups in the Galapagos Islands chain were lost during the 1982-83 El Nino event. Territorial male mammals also suffer because of their inability to follow the migrating food sources.
The widespread change in ocean currents to accommodate low-level wind field changes are further illustrated by the fact that in 1983, a triggerfish was spotted 2,800 km (more than 1,700 miles) farther north than any other triggerfish had been sighted. The fish must have followed the warm currents fed by the ENSO event northward from the tropics. This put a tropical fish in an area associated with almost arctic waters offshore of Alaska.
The above examples of ocean current changes will, in turn, illuminate another problem area for tactical decision planners. If warm and cold water ocean currents are changing their intensity and position depending on whether an ENSO event is occurring (along with which type of ENSO event it is), then the normal "string" of warm and cold water eddy pools associated with these currents also will change. Since submarines can hide in or near such conditions, anti-submarine tactics and techniques will have to be modified in order to more accurately reflect these ocean current changes. Shipping lanes will have to be modified, not only for ocean current speed and direction changes, but to ensure the highest possible safety margin for the ships, crews, and materiel in transit. Admirals on both sides of the Pacific have made a specific point to note the tactical advantages of understanding such data base changes as quickly as possible (Endnote 1).
The change in weather patterns on the Korean Peninsula, when a moderate to strong ENSO event is in progress, results in a short-term climate shift that is best characterized as warm and dry (Figure 15). As noted in the four stations from South Korea during the May-September time frame (Figure 16), the precipitation values, with one exception, showed drier than normal values. It should be noted that the four El Nino periods used are rated the most severe of the last twenty years. At the same time, the west-to-east movement of the storm tracks across the northern Pacific Ocean become very noticeable in the areas of California, near San Francisco and Los Angeles. This can be noted by examining the results from over 20 primary National Weather Service reporting stations and related military weather stations along the central and southern California coastline. There, the precipitation amounts are all above normal (Figure 17), again using San Francisco and Los Angeles as specific examples. Once the ENSO event ends, the weather pattern will return to a more normal sequence. Southern California returns to a dry condition, and the Korean Peninsula becomes very wet from the increased frequency of tropical storms, as the storm tracks return to the western Pacific.
This region of the world is highly dependent on and sensitive to rice production for an ever enlarging population. The most recent example of a negative impact was the news in 27 May 1995 newspaper articles dealing with Japan's exporting rice to the People's Republic of Korea (i.e. North Korea). "The North is said to be importing rice already from Thailand, China, and South Korea." A North Korean government spokesperson (being refreshingly candid), was quoted as saying "North Korea is facing grain shortages due to bad weather" (Reference 2). The double-edged sword is that within 2 years of an ENSO event, the warm dry environment is replaced by a warm wet scenario. This is brought on by an increased frequency of heavy rainfall amounts in the summer/fall time frame, as more frequent tropical storm/typhoon actions move through the Korean Peninsula.
Since the topography of the Korean Peninsula is mainly mountainous, any tropical storm/typhoon damage is rarely wind related; it is usually damage from heavy rains and the resultant flash flooding. Amounts of 10 to 20 inches or more can be quite common. The record is more than 31 inches in one 24-hour period (31.25 inches of rain fell on Camp Page, South Korea on 19 July 1988). Our military superiority is based, in large measure, on our electronic umbrella that is backed up with a ground presence of mobile infantry and mechanized heavy weapons. Both advantages, particularly our firepower advantage, are quickly negated during a 24-hour period that produces 20- to 31-inch rainfall totals (Reference 3) . Thus, for one 24-hour day, our electronic surveillance and air superiority are negated by the effects of an ENSO-related tropical storm/typhoon path that produces such large amounts of rain. For days afterward, our mobility Tactical Decision Aids (TDA's) have no real relevancy to the current topographical situation! The TDA's for the proper placement of mechanized or armored tank battalions will suddenly become highly suspect (since most of Korea's natural soil surface is composed of clay composites that quickly turn to deep mud during this type of heavy rainfall) (Reference 3). The ability to implement short-term logistics support, such as Logistics-Over-The-Shore (LOTS) operations for both men and machines, will need review. Long-term support of the IX Corps logistics mission in Japan, in particular, the ability to use heavy weapon transports such as the "roll on - roll off" models (commonly referred to as RORO's), will be effected by multiple tropical storm/typhoon events (Endnote 2). Ship routings will be slow and complex, at best, as shown by the satellite shot taken on 14 September 1967 ( Figure 18). As each storm generates its own set of storm waves, the overall sea conditions become even more chaotic as the four storms in the western Pacific meet the waves generated by the two storms in the eastern Pacific.
This could literally lead to the sudden loss of a heavily loaded ship due to an ocean mechanism that the scientific community continues to investigate. As certain hurricanes or typhoons approach a strong warm water current, such as the Atlantic's Gulf Stream or the Pacific's Kuroshio current, the energy of the warm water seems to complement the storm surge wave in order to produce rogue-like tsunamis that can approach 100 feet in height on the open sea! The right conditions are most likely to occur along the area of the main warm water current known as the "north wall." This phenomenon has been noted in a narrow band of extreme horizontal water temperature changes marking the north edge of the Kuroshio current in the Pacific Ocean and the Gulf Stream in the Atlantic Ocean (Reference 4). A recent case in point is the 16 September 1995 newspaper account of the British luxury liner, Queen Elizabeth 2, as she made another passage from the U.S. to Europe. "The 95-foot wave, caused by the seas being whipped up by Hurricane Luis, hit the ship bow-on while it was south of Newfoundland. The wave was so huge that its crest was at bridge level" (Reference 5). Thus, the sudden loss of a heavily loaded SL - 7, the largest of the RORO's, is not outside the realm of possibility (Endnote 2).
Another example of the strength and reach of these storms involves slow-moving tropical storms off the southeast coast of Australia in the Tasman Sea area ( Figure 7) which can generate wave patterns that can significantly damage the beaches on the Hawaiian Islands, and the next day, begin damaging the beaches around the naval facilities in San Diego, CA.
A particularly extreme example of western movement before recurvature, with excessive rainfall over the Korean Peninsula, involved tropical storm "June" in August 1984 ( Figure 26). As it entered mainland China, west-southwest of Taiwan, the remains of June encountered an unusually strong, and consequently "further south than normal," polar cold front. This combination of polar air and a very moist tropical system acted as a giant conduit that funneled heavy rains over the Korean Peninsula, even though the actual tropical storm system was now far below the standards usually associated with a "named" storm. This flooding claimed 180 lives and drove 90,000 people from their homes (Reference 7).
Another problem to consider with strong typhoons is heavy rainfall amounts, coupled with high winds (approaching 150 mi/h), and landfall near high-density population centers. Two such events in the Tokyo, Japan area killed 1,269 people in 1958 and 5,098 in 1959. The inevitable confusion that surrounds such natural catastrophes would slow down any attempt to resupply that area. This, in turn, could easily be interpreted as a military weakness to be exploited by armies of North Korea, if such an event occurred near Seoul or Pusan, South Korea.
It is important to remember that the North Korean military leadership of 1950-54 believed so strongly in the importance of weather data as a strategic weapon that they tried to eradicate any external knowledge of Korean weather or climate data. It is the only conflict that the author has studied in which a concerted effort was made to either move weather libraries, in this case to North Korean military bases, or to destroy those libraries wherever they were found. Of more profound importance was the fact that any South Korean weather personnel, if captured, were summarily executed (Reference 8). With this type of extreme behavior toward weather personnel and weather data bases, strategic and logistic planners should remember that North Korean military planners will be strongly inclined to use their knowledge of local weather patterns to help negate any U.S. military advantages.
Considering world history, it is reasonable to note that a nation that is hungry will gradually come to the conclusion that its armies can solve the problem. Our dependence on electronic surveillance, early warning systems, and jamming countermeasures to protect our troops and equipment will be most vulnerable during the heavy storms that are possible during the final months of an El Nino event. Dr. Epstein's work on the gradual expansion of the average minimum temperature line (10 ° C. [50 ° F.]) in both its area and its vertical sense, is the best analytical proof yet that we are undergoing a very gradual, but steady, global warming effect. More heat energy put into the atmosphere causes more energy to be stored in the world's oceans. This, in turn, makes it easier for tropical storms to grow larger and become more intense. The meteorological values for the Korean Peninsula are not extreme for Southeast Asia, but the following values could be recorded in South Korea if conditions were to complement each other.
The conditions to watch for would be the following:
Thus, the final tactical decision formulations should be based on the following areas of significance:
If a ruling group within North Korea has enough internal economic pressure, it becomes easier to blame "the enemy" for their problems. Especially if they think the U.S. is preoccupied with other world events, it becomes easier to believe that strategically we are not ready. It is, therefore, only a short step to "victory" to use a strong typhoon to cover their initial advance into South Korea (Reference 11). In the midst of winds, heavy rains, mud, and floods, chaos will rule. For their goals, the more chaos the better. The technical superiority of our satellite and communication systems was very evident in the U.S.'s execution of "Operation Desert Storm." To ignore this advantage is a mistake any potential adversary will try hard not to repeat. Thus, our strategic and logistical planners need to remember the potential problem areas for each area of concern, as noted by our use of the Korean Peninsula (note Table 6).
The U.S. must understand that an El Nino event is not a threat; however, it is the catalyst that can lead to a real threat. It could be the start of a dangerous game of military brinkmanship brought on by economic hardship, and fueled by a mutual feeling of suspicion and mistrust. If military planners acquire a better understanding of the immediate and long-range effects of an El Nino mechanism, then strategically and logistically the U.S. will continue to have a strong deterrent force in the western Pacific area of operations, regardless of any "current" (i.e. typhoon) weather situation. Typhoon Oscar (inset photo), should continue to be a potential economic concern; it should not be allowed to become the first step in a reenactment of the 15 September 1950 amphibious landing at Inchon.
B "It is my responsibility to ensure that every Soviet submarine understands the ocean and how to hide in it." (Rear Admiral A.I. Russokho, Soviet Oceanographer, Paris, France, 1973).
A
The fastest RORO is the SL-7 which can average 33 kn.
B
The average speed for most of these ships is 15-17 kn.
C
Most RORO designated ships have a length of 500 ft.,
a width of 35 ft., and a draft of 28-30 ft.
D
On a normal great circle route, storm
generated sea swells will cause significant
delays in the recurve area.
E
If the RORO ships are ordered to move
east, they can expect a delay in travel time
of at least 2 1/2 - 3 weeks because of the
Panama and Suez Canal transits.
F
If the southern route around the Cape of Good
Hope is used, the worst case scenario would
add another 20 days to the time interval,
in addition to possible superstructure damage to
individual vessels due to winter storm conditions
(Reference 6).
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Author: John Neander
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