Archive by Author | Kevin Wood

USS Salt Lake City: 1941

Here’s a first look at the navigation and temperature data from 1941 you’ve transcribed from the logbooks of the USS Salt Lake City (CA-25), a heavy cruiser commissioned in 1929. The Salt Lake City was 585 feet long and capable of making 33 knots on four steam turbines (107,000 horsepower).

The processing code used to convert Zooniverse classifications into transcription-verified and quality-controlled data was written by science team member Praveen Teleti. There are 8,760 hourly marine weather records (WRs) in this series, the first installment on roughly 832,000 WRs (~580,000 are ready for processing as of August 2021) transcribed from only our 19 ships. This is more than the total number of U.S. Navy WRs from the WWII era currently available in the global standard dataset – ICOADS (the International Comprehensive Ocean Atmosphere Data Set).

The track of the Salt Lake City for 1941 is shown in Figure 1. The first two months of the year were taken up by an extended overhaul in the Mare Island Naval Shipyard. In March the ship moved to Pearl Harbor and spent considerable time in training exercises in the area of the Hawaiian Islands. One cruise was made to Midway Island on March 17. In July and August Salt Lake City and USS Northampton (CA-26) made a voyage to Brisbane, Australia, for training and likely intelligence gathering around New Guinea. In early December Salt Lake City was part of Task Force 8 with the aircraft carrier Enterprise (CV-6), two other cruisers and nine destroyers assigned to deliver a squadron of fighter planes to Wake Island. On the way back on December 5-6 the task force was delayed by stiff easterly winds and rough seas and so was still at sea on December 71.

Figure 1. The track of the USS Salt Lake City for 1941. (Map: P. Teleti)

Figure 2 shows the plots of the air (blue) and seawater (orange) temperatures from the ship’s deck log, before and after initial quality control checks. The periods the ship was in port are indicated by the grey broken line. These data are nearly all from the neutrality period prior to the U.S. entry into World War II, in December 1941. Nevertheless, the logbooks show that the Salt Lake City was frequently operating in ways consistent with a wartime footing, including ‘darkened ship’ that may affect how some weather readings were made.

The most obvious difference between the uncorrected data (top) and quality-controlled data (bottom) is the frequency of large departures in the former. These seem to be associated most often with various typewriter key miss-strikes, especially the key next door (like 1 or 3 instead of 2). These have been corrected, but other characteristics of the data will need further examination, particularly relating to the seawater temperatures measured in the main engine room cooling water injection.

Figure 2. Air (blue) and seawater (orange) temperatures recorded in the USS Salt Lake City deck logs, January though December 1941. The top panel shows the data prior to initial quality checks, and the lower panel after one round of adjustment.

Also notable, but not surprising, is the difference between ‘at sea’ and ‘in port’ air temperatures. The higher values in port are likely the result of low air circulation in the thermoscreen, combined with a multitude of heating factors on the ship itself, and heat island effects within urbanized ports. The low values, seen for example during the September period in Pearl Harbor, are more puzzling. The period the ship was in Brisbane is marked by an especially wide daily temperature range (between ~45° and 69°), but this is well within cool season climatology for this location. A photo of the Salt Lake City alongside in New Farm, Brisbane, during this visit is shown in Figure 3.

Figure 3. The USS Salt Lake City alongside in New Farm, Brisbane, August 5-10, 1941. The ship is painted with a false bow wave, a form of camouflage. Two of four Curtis SOC Seagull scout planes are visible amidships. (Photo: Naval History and Heritage Command NH 80837)

There is a curious historical event along the ship’s track on the return voyage from Brisbane. After sailing the ship made two brief stops, possibly clandestine, to reconnoiter Port Moresby and Rabaul, in New Guinea. At the latter, Salt Lake City came to anchor on 16 August, somewhere near the port (the place names and bearing marks were left intentionally blank in the typed logbook). Three Seagull scout planes were launched, missions undeclared in the log. These places would become incredibly important to the defense of Australia and other Allies with the outbreak of war just three months later. A new analysis of pre-war planning by the Navy suggests some officers were well attuned to the dangerous situation in the Pacific that summer but were unheeded by policy makers2.

  1. Historical information from Naval History and Heritage Command (NHHC), Dictionary of American Naval Fighting Ships, available online at
  2. NHHC (2021): Richmond Kelly Turner, Planning the Pacific War. U.S. Navy Operations in World War II. OPNAV Support Section, Histories Branch. Retrieved 16 August 2021.

War Diary

On October 19, 1942 the Commander in Chief of the Navy issued new guidance to the fleet regarding the ship’s logbook. His order, COMINCH 3899, directed that the logbook be divided into three sections: Part I Columns (the weather page); Part II Administrative Remarks (routine business like personnel changes), and; Part III Operational Remarks (War Diary) CONFIDENTIAL. Part III was to be kept separate from the other two sections. A typical example is shown in Fig. 1. It is notable that this document series was only formally declassified by the National Declassification Center a few years ago.

The purpose of this change was to decrease the likelihood that useful intelligence could be gleaned if the ship’s logbook fell into the wrong hands. In the first days of the war there were six U.S. Navy ships that were scuttled in shallow water and later salvaged by the Japanese Navy, and one captured outright, the USS Luzon (PR-3). During 1942 several S-class submarines were also accidentally grounded and abandoned in hostile territory. But perhaps the stunning success of the British Royal Navy capturing German naval codebooks and all-important Enigma machines in 1941 was the main inspiration. More about this in The Guardian.

Figure 1. An example of a War Diary from the destroyer USS Macdonough from 1 November 1943. On this day the Macdonough departed Pearl Harbor to join Task Force 52 en route to the Gilbert Islands and the invasions of Tarawa and Makin Island.

The key point for our purposes is after late 1942 the navigation data does not appear on the Part I weather page except as a single noon notation expressed only in whole degrees. The detailed navigation data was moved to the War Diary. The 3899 directive was in force until the spring of 1944, when the logbook format returned to something close to the historical pattern, insofar as the navigation data was moved back to the weather page.

Due to the time lag in getting new format log sheets out to the fleet in 1942, and again in the spring of 1944, there is considerable variance in when a particular ship’s logbook reflects these changes. Moreover, when COMINCH 3899 was issued, there were no pre-printed sheets for the new scheme available at all, so for several months the War Diary was typed out on a blank sheet that roughly followed the new instructions.

All this means that the workflow we’ll use to capture the navigation data during this period will need to be quite flexible. However, a benefit for those interested in the ship’s stories is that the War Diaries will soon be part of a new Navigation workflow. As you will see, these first-hand accounts can be extraordinarily compelling, even when written in the normally dispassionate language of the ship’s logbook.

Finally, the separation of the navigation data from the weather pages of the logbook may have affected the amount of U.S. Navy weather data originally key-punched by the Weather Bureau in the early 1950s, and later migrated into the present International Comprehensive Ocean-Atmosphere Data Set (ICOADS). Since only weather observations associated with a ship’s position were punched, loss of collation with the navigation data may well be a factor. Departures in the number of observations per day captured in ICOADS during and after the period COMINCH 3899 was in force (Figure 2) is suggestive of such a loss. This further supports the need for the data (and metadata) recovery we are working on together.

Figure 2. Time-series of the number of U.S. Navy daily weather observations key-punched by the Weather Bureau and migrated into ICOADS Deck 195. Marked changes in the number of observations captured per day occur at the beginning and end of the period COMINCH 3899 was in force, and most dramatically at the conclusion of the war in Europe (VE), when the Navy rapidly drew down the number of ships in the Atlantic Ocean.

A winter reflection

An old shipmate of mine shares this poem every December, and it always makes me pause to reflect on my former career at sea, and those friends I’ve sailed with now scattered far and wide. And us Old Weather shipmates have also seen plenty of stories like this along the 45 million or so miles of ship tracks we’ve covered over the past ten years. Some, like that of the USS Jeannette, a worse tale. My own encounter with the hard edge of the ocean was on the distant rocky shore of a small island in the Beagle Channel, the strait in Tierra del Fuego named, appropriately, after the HMS Beagle. We were holed from stem to stern, but thanks to the ship’s engineers, lots of pumps, and an ice-strengthened hull of inch-and-a-half thick steel, it came out okay in the end. So as this horrible pandemic year draws to close, I say, shipmates, let us hold with hope – we will clear this weary headland and find the open sea again.

Christmas at Sea, by Robert Louis Stevenson, first published on December 22, 1888

The sheets were frozen hard, and they cut the naked hand;
The decks were like a slide, where a seamen scarce could stand;
The wind was a nor’wester, blowing squally off the sea;
And cliffs and spouting breakers were the only things a-lee.

They heard the surf a-roaring before the break of day;
But ’twas only with the peep of light we saw how ill we lay.
We tumbled every hand on deck instanter, with a shout,
And we gave her the maintops’l, and stood by to go about.

All day we tacked and tacked between the South Head and the North;
All day we hauled the frozen sheets, and got no further forth;
All day as cold as charity, in bitter pain and dread,
For very life and nature we tacked from head to head.

We gave the South a wider berth, for there the tide-race roared;
But every tack we made we brought the North Head close aboard:
So’s we saw the cliffs and houses, and the breakers running high,
And the coastguard in his garden, with his glass against his eye.

The frost was on the village roofs as white as ocean foam;
The good red fires were burning bright in every ‘long-shore home;
The windows sparkled clear, and the chimneys volleyed out;
And I vow we sniffed the victuals as the vessel went about.

The bells upon the church were rung with a mighty jovial cheer;
For it’s just that I should tell you how (of all days in the year)
This day of our adversity was blessed Christmas morn,
And the house above the coastguard’s was the house where I was born.

O well I saw the pleasant room, the pleasant faces there,
My mother’s silver spectacles, my father’s silver hair;
And well I saw the firelight, like a flight of homely elves,
Go dancing round the china-plates that stand upon the shelves.

And well I knew the talk they had, the talk that was of me,
Of the shadow on the household and the son that went to sea;
And O the wicked fool I seemed, in every kind of way,
To be here and hauling frozen ropes on blessed Christmas Day.

They lit the high sea-light, and the dark began to fall.
“All hands to loose topgallant sails,” I heard the captain call.
“By the Lord, she’ll never stand it,” our first mate Jackson, cried.
…”It’s the one way or the other, Mr. Jackson,” he replied.

She staggered to her bearings, but the sails were new and good,
And the ship smelt up to windward just as though she understood.
As the winter’s day was ending, in the entry of the night,
We cleared the weary headland, and passed below the light.

And they heaved a mighty breath, every soul on board but me,
As they saw her nose again pointing handsome out to sea;
But all that I could think of, in the darkness and the cold,
Was just that I was leaving home and my folks were growing old.

A new Old Weather project

Old Weather – WW2 is now an active Zooniverse project. The purpose of this project is to recover hidden marine weather data recorded in U.S. Navy ships’ logbooks during World War II. Like all Old Weather projects, these data will be used to drive sophisticated computer models that help us understand and reconstruct weather and climate in extraordinary detail. But there is another goal that is just as vital – to uncover the source of a mysterious distortion in sea-surface temperature data collected during the war.

This distortion, which Chan & Huybers refer to as the World War II Warm Anomaly, may not be physical in nature, but, they argue, arises from earlier bias adjustments applied to correct for differences in sampling methods. The age-old technique of hauling up a bucket of seawater then taking its temperature on deck produces a different value compared to those collected from an engine-room cooling water intake, for example. There may even be differences in values because of the characteristics of particular ships, especially how deep they sit in the water (their draft). So knowing the fleet composition within the data set, and the specifics of how the measurements were made is crucial to teasing out an answer.

Because of the work we’ve been doing with the U.S. National Archives over the past eight years or so we are in a unique position to help investigate this question – we have digital images of many of the original U.S. Navy logbooks. The logs we are transcribing in this project were selected because the ships were often in the same place at the same time, even moored alongside each other in nests. All but two survived the entire war, 1941-1945. Twelve were based at Pearl Harbor in 1941, eighteen were in the Aleutian Islands in 1942-1943, and ten were caught in Typhoon Cobra in December 1944. This opens up many opportunities to investigate sources of bias, from factors associated with different ship types, the weather instruments in use at different times, or changes in methods required by wartime operations (such as blackout for example). It will also be possible to investigate how tropical and sub-polar environments may have influenced the data in different ways.

Moreover, with logbooks in hand, we can also better understand legacy issues associated with U.S. Navy data key-punched onto IBM cards in the early 1950s and subsequently migrated into today’s widely used International Comprehensive Ocean Atmosphere Data Set (ICOADS). Already we have found out that the fleet composition represented in ICOADS is tilted toward submarines, destroyers, and destroyer escorts. Aircraft carriers, with probably the best-equipped and best-trained weather personnel in the Navy, appear to be mostly neglected.

The World War II Warm Anomaly is large enough to appear in the long-term global mean sea-surface temperature record. This presents as an aspect of natural variability that may not in fact be real. If this turns out to be true, the corrected temperature record would appear to evolve upward more smoothly over time, and correspond more closely to model results as described by Chan & Huybers.