Kn-Kz

 

KNMI

Abbreviation for the Royal Netherlands Meteorological Institute (i.e. Koninklijk Nederlands Meterologisch Instituut). See the KNMI Web site.

 

knot

A speed of 1 nautical mph. It is equal to 1.15 mph or 1.85 kph and used in navigation and meteorology.

 

Knudsen number

More later.

 

koembang

A fohn type wind found in Java, where it has been known to damage sensitive crops, e.g. tobacco.

 

Koeppen scheme

A bioclimatic classification scheme that divides climates into six broad groups according to the major vegetation types associated with each. The groups are broadly determined by critical temperatures and and the seasonality of precipitation. The groups are:

A

Tropical rainy climates with T in the coldest month higher than 18 C.

f

PPT in driest month at least 60 mm.

m

PPT in driest month less than 60 mm but equal to or greater than (100-r)/25 where r is the annual average PPT.

w

PPT in driest month less than (100-r)/25

B

Arid climates where 70% of annual PPT falls in warmer 6 months and r/10 less than 2t+28 (where t is the annual average T in deg. C), or 70% of annual PPT falls in cooler 6 motnsh and r/10 less than 2t, or neither half of year with more than 70% of annual PPT and r/10 less than 2t+14.

W

r less than one half of the upper limit of applicable requirment for B.

S

r less than upper limit for B but more than one half of that amount.

h

t greater than 18 deg. C.

k

t less than 18 deg. C.

C

Warm, temperate, rainy climates in which the T in the coldest month are between 0 and 18 deg. C, and in the warmest month higher than 10 deg. C.

s

PPT in driest month of summer half of year less than 40 mm and less than 1/3 of the amount in wettest winter month.

w

PPT in driest month of winter half of year less than 1/10 of the amount in wettest summer month.

f

PPT not meeting conditions of either s or w.

a

Average T of warmest month 22 deg. C or above.

b

Average T or each of four warmest months 10 deg. C or above; T of warmest month below 22 deg. C.

c

Average T of from one to three months 10 deg. C or above; T of warmest month below 22 deg. C.

D

Rainy climates typical of boreal forest, in which temperatures in the coldest month are lower than 0 deg. C, and in the warmest month higher than 10 deg. C.

s

Same as under C.

w

Same as under C.

f

Same as under C.

a

Same as under C.

b

Same as under C.

c

Same as under C.

d

Average T of coldest month below -38 deg. C.

E

Tundra, in which T in the warmest month are below 10 deg. C.

T

Average T of warmest month between 10 and 0 deg. C.

F

Average T or warmest month 0 deg. C or below.

H

T requirement same as E, but to due altitude effects.

 

kosava

A ravine wind occurring on the Danube, southeast of Belgrade.

 

kraton

See craton.

 

Kruzenshtern Strait

See Okhotsk Sea.

 

krypton-85

A radiactive inert gas with a half-life of 10.76 years that is useful as a tracer in ocean studies. It forms when uranium and plutonium undergo fission, making its chief atmospheric sources nuclear weapons testing and nuclear reactors used for commercial power and weapons plutonium production. Most of the krypton-85 sources are located in the northern hemisphere which, due to slow mixing across the ITCZ, has about a 20% higher atmospheric concentration than does the southern hemisphere.

Its source to the ocean is well known due to extensive measurements of the atmospheric concentrations over time. This, along with its chemical inertness, are valuable properties for an ocean tracer to have. It enters the ocean by gas exchange, equilibrating with surface water on a time scale of about one month. This equilibrium concentration can be calculated from krypton solubility, a function of temperature and salinity, and from the atmospheric krypton concentration. This procedure won't apply in regions of rapid vertical mixing since the surface water doesn't have time to come into equilibrium with the atmosphere, but direct measurements in those regions can alleviate this problem. A measurement requires a water volume of 250 l, and the dynamic range of the measurement of krypton-85 (i.e. the ratio of the surface water concentration to the minimum detectable amount) is around 100. Measurement precision is +/- 4% for surface samples and +/- 25% for samples with concentrations 3% that of surface water.

Kr-85 is used as a tracer for study processes that occur on a decadal time scale, e.g. thermocline ventilation, mixing, circulation, and deep water mass formation, due to it being introduced to the atmosphere only in the last 35-40 years. See Sarmiento (1988) and Broecker and Peng (1982).

 

K-T extinction

See Cretaceous-Tertiary extinction.

 

Kuroshio Current

In oceanography, a western boundary current located in the western North Pacific Ocean. The Kuroshio begins where the North Equatorial Current approaches the Philippines and continues northward east of Taiwan. It then crosses a ridge between Kyushu and the Okinawa Islands, responding by forming the East China Sea meander, and proceeds through the Tokara Strait, after which it takes a sharp turn to the left (north). At this point it takes one of three alternate paths - a straight path, a path with a small meander, and a path with a large meander. It changes between the first two paths about every 18 months, a pattern broken every few years at irregular intervals when it switches to the large meander path. It then continues until it separates from the coast and turns east at about 35 deg. N, at which point it technically changes into the Kuroshio Extension. The Kuroshio Current is part of the overall wind-driven subtropical gyre circulation cell that exists in the North Pacific Ocean. This has also been called the Black Stream and the Japan Stream. See Tomczak and Godfrey (1994).

 

Kuroshio Extension

That which the Kuroshio Current becomes when it separates from the continental rise at about 35 deg. N in the western North Pacific Ocean. It flows eastward from this point as a strong jet which, given the proclivities of such things, evinces a strong instability. This is seen in two regions of north- and south-ward shift called the ``First Crest'' and the ``Second Crest'', centered at approximately 140 deg. E and 152 deg. E, respectively, with a node near 147 deg. E. East of these features the Shatsky Rise produces another region of alternate (but less regular) paths, followed by a passage over the Emperor Seamounts where it breaks up into filaments which partly comprise the North Pacific Current. The Kuroshio Extension is part of the overall wind-driven subtropical gyre circulation cell that exists in the North Pacific Ocean. See Tomczak and Godfrey (1994).