Transcript Document 7466436

Learning from History
• So impossible is to keep our heads above
the rising tide of the new meteorological
literature that we are neglecting, to our loss,
the rich stores which lie buried in the books
of a generation ago.
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Robert De C. Ward (Harvard U.)
Monthly Weather Review, Jan. 1914 p.23()
Hazy Weather in the Autumn:
Indian Summer
• Dry haze is undoubtedly due to fine
particles of dust composed of:
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fine particles soil
smoke and ashes from fires
salt from ocean spray
germs and fungi
• Mo. Weather Rev. Aug. 1901(1243)
Vertical Transport and Dispersion
• During the daylight the sun warms the soinl
which heats the adjacent air and the rising
currents carry the dust up to 300, 5000 and
7000 feet with well defined upper surface.
• Mo. Weather Rev. Aug. 1901(1243)
Horizontal Transport and Dispersion
• If a general wind is blowing this will bring
abundance of fresh air and the haze is
diminished but spread over a larger area.
• If there is no general wind as for instance in
the midst of areas of high pressure, then the
layer of dust reaches higher each successive
day. This is the general explanation of the
dry haze weather ‘Indian Summer’
• Mo. Weather Rev. Aug. 1901(1243)
Removal
• The amount of dust in the air depends on
the balance between the settling by night
and rising by day [implication dust settles
out every night] (1243)
Dust in Fiume, March 1901
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Examination under polarizing microscope
(640x) showed mostly colorless and some
colored, irregular fragments of crystals
together with skeletons of
microorganisms and small particles of
soot. The color of the collected dust was
bright reddish brown.
The dust fall averaged between 260 and
1400 g/m2 in Fiume.
Dust of Fiume belong to the same class
as the Trade Wind dust which blows from
Africa over the Atlantic and the one
collected on May 30 1892 in Sweden.
The dust produced a reddish haze, to
diminish the insolation and thereby
doubless increasing the air temperature in
the upper strata. [no backscattering?]1242
Chemical Mass Balace
Sahara Dust at Fiume, March 10-13 1901
M. Barac (1242)
Si O2
Al2 O3
Ca O
Fe2 O3
C O2
Mn3 O4
Mg O
Organics
Traces
Sahara Dust Transport
• One can easily see that we have here to do with a severe
storm in the Sahara region, and by the attending winds the
finer dust was raised and transported northward.
• In January 1890 the steamship Queensmore arriving at
Baltimore from England, reported red rain and red dust off
the coast of Newfoundland. It would be very remarkable if
this was Sahara dust.
• The dust was examined by Prof. Perhanz both
microscopically and chemically and found to be perfectly
similar to the sands of the Desert of Sahara, described by
many authors.(1240)
Volcanic Aerosol: Dust or
Droplets?(1251)
• The beautiful sky colors produced by
volcanic aerosol from Krakatoa and Pelee
must have been produced by droplets of
condensation.
• It would require a long mechanical
grinding to make a uniformly fine
impalpable powder
Editor, Mo. Weather Rev. Jul 1990 CA 1234
• During the mid 1800s, dust was of interest more to the geologists
than to meteorologists.
• By the late 1800s meteorologists recognized that aerosols are
essential parts of the atmosphere.
• The presence of dust facilitates rain and snow formation
• Influences the visible and thermal radiation.
• Specifying the composition of the air should be expanded from
gaseous chemical composition to include the aerosol
Rafinesque:
Thoughts on Atmospheric Dust (1818)1234
• Dust is falling from the atmosphere all the time
• Dust exists on the tops of the highest mountains
• A portion is formed chemically in the atmosphere by combination of gases and
elementary particles dissolved in in the air, sometimes rapidly
• Its accumulation is is thick in the lower strata of the atmosphere
• It settles slowly to the ground in clear weather but is quickly washed down by
rain and snow
• Some dust is from the pulverization of of road and field surfaces
• Other dust comes from materials in the activity of mankind but whence arises
the dust observed by means of sunbeams?
• Just as the sea deposits particles that eventually form rocks so the air deposits a
more delicate pulverulent matter.
Dialog of Rafinesque:
• Anonymous comment(1920): All dust comes from the action of the
wind, even the dust seen at sea has the same origin, being carried 1500
miles over the Atlantic
• Rafinesque: I do not deny that the winds raise terrestrial dust and often
carry it to distance; but I assert that … as dust exists in the atmosphere
as far as the clouds at all time, I venture to believe, with Virey, Patrin,
Deluc, and other philosophers, that there must be another independent
formation of dust in the besides the scanty terrestial supply wafted by
the winds.
Rafinesque: The Rays of Sun
• The sun rays are not an
optical reflection from the
atmosphere since it is
brighter and not so azure.
It must be dust.
• The phenomenon can be
seen even after long and
heavy rains which must
have precipitated all the
terrestrial dust to the
ground.
• Whence the dust must be
continually formed
formed in the atmosphere.
Rafinesque, 1820: Gas-Particle Conversion
• The insights given by modern chemistry into the gaseous formations of
solid substances will be amply sufficient to to account for this
spontaneous formation.
• We know that sulfur, muriate of ammonia, etc. can be formed by
sublimation of gases
• That smoke soot, manna, volcanic productions, meteorites, earths, and
even stones or metals may be spontaneously combined by a casual
meeting of gaseous emanations.
• It is not, therefore, difficult to conceive how dusty particles may be
formed in the great chemical laboratory of our atmosphere.
Aitken, 1894: Photo-Nucleation
in Britain
• On cloudy days the nuclei count remained low
• The number increased with sunshine, in proportion to the
sunshine which occur during anticyclonic conditions.
• Sunshine may produce some change in the constituents of the
atmosphere which gives rise to nuclei formation in saturated air.
• The high nuclei days were not hazy which suggests that the
nuclei were of molecular dimensions
Aitken, 1894: Nuclei-Visibility Relationship
• It has been the custom to record the limit of visibility.
• Observations on rainy days were discarded
(Kingairloch)
• The data were classified according to humidity
• The amount of haze was proportional to the number of
particles
• Hence (Nuclei x Visual Range) = Cont.
• In dry air C is 2x the the value for moist air
Aitken, 1894: On Aerosol Sources and Removal
• Densely-inhabited areas lose their purity
• Purifying areas of the world are those regions that lose
more impurity than they gain.
• Much of the dusty impurity discharged into our
atmosphere falls to the ground but much is so fine that
it will hardly settle.
• The deposition of vapor on these particles seems to be
the method adopted by nature for clensing them away.
• Hence cloudy and rainy regions are the most purifying
areas
Meteoric
• It is well recognized that permanent
addition to our globe, doue to showers and
myrids of meteors is probably equivalent to
not less than 1 inch/century for the globe..
And all this is carried to the bottom of the
ocean.(1234)
Kempf, 1914 Regional Haze
Die Entwicklung der Therorien uber Hochenrauch
The Development of Theories on Regional Haze
up to 1870
Dissertation by N. Kempf (1914)
Regional haze is a strong haziness of relatively dry
air with large spatial extent and longer duration.
Kempf, 1914: Theories on the
Cause of Regional Haze
1. Emissions of non-aqueous vapors from the
Earth surface (earthquakes)
2. Volcanic Ash
3. Cosmic Ash
4. Windblown Dust
5. Combustion Processes
6. Electricity +
Prestel, 1861: Peat Smoke Episode
Egen, 1828: Establishing SourceReceptor Relationship
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Smell: If it smells like smoke..[chemical composition]
Temporal Trend:
Decay with Distance:
Wind Direction:
Direct evidence:
Time-Space correlation
The 19th Century Atmospheric Aerosol Science:
From Confusion to Modern Science
• There was a confusion as to what aerosols were and where do they
come from. By the late 1800 the major aerosol source types,
windblown dust, sea salt, combustion smoke and soot, secondary fine
particles, were identified, but not quantified
• Aerosol properties
• Unique air pollution problem of North Central Europe: Regional
smoke palls from peat burning
1700-1900:
From Enlightenment to Modern Science
• 1700 - 1800: Era of Enlightenment. Emergence of
naturalists, architects, engineers, geographers and
many new ideas, good and poor.
• 1800-1850: Transition form theory-driven to
observation and later data-driven atmospheric
aerosol science
• 1850-1900: Consolidation of theories by weeding
out the unsubstantiated ideas.
Haze form Gaseous Emissions from the Earth
• Mostly attributed to bursts of emissions during earthquakes.
• I. Kant (1756) in Locarno, IT: In two hours a hot reddish haze has
spread over the valley which turned into red rain, which beyond
doubt, is linked to earthquake activity.
• Marconelle (1783): Rapid springtime warming of the earth caused
the emission of fermentation products to the atmosphere. Once the
water was evaporated by the sunshine, only the solid particles
remained which formed the ‘dry fog’. The dry fog covers large
geographic areas due to the large extent of the missions [not due to
long range transport].
Haze from Volcanic Emissions
• Seneca (ca. 60 AD) has noted that Volcanic
gases and ash cause atmospheric turbidity.
• However, only in the 1700s was is
suspected that volcanic aerosol is spread
over large area.
• B. Franklin has noted that the haze in 1783
may have been due to an eruption in Island.
Volcanic Aerosol and Global
Circulation
• The 1883 Krakatoa eruption
• Kiessling
• Global Ciculation