Early work (1964–1972) Richard Lindzen

1 work (1964–1972)

1.1 ozone photochemistry
1.2 atmospheric tides
1.3 quasi-biennial oscillation
1.4 superrotation of venus

early work (1964–1972)

lindzen s work concerned ozone photochemistry, aerodynamics of middle atmosphere, theory of atmospheric tides, , planetary waves. work in these areas led him number of fundamental scientific discoveries, including discovery of negative equivalent depths in classical tidal theory, explanations both quasi-biennial oscillation of earth s stratosphere , four-day period of superrotation of venus atmosphere above cloud top.

ozone photochemistry

his phd thesis of 1964 concerned interactions of ozone photochemistry, radiative transfer , dynamics of middle atmosphere. formed basis of seminal radiative , photochemical processes in mesospheric dynamics published in 4 parts in journal of atmospheric sciences between 1965 , 1966. first of these, part i: models radiative , photochemical processes, co-authored harvard colleague , former phd thesis advisor, richard m. goody, known 1964 textbook atmospheric radiation. lindzen , goody (1965) study has been cited foundational in exact modeling of middle atmosphere ozone photochemistry. work extended in 1973 include effects of nitrogen , hydrogen reactions former phd student, donna blake, in effect of photochemical models on calculated equilibria , cooling rates in stratosphere.

lindzen s work on ozone photochemistry has been important in studies @ effects anthropogenic ozone depletion have on climate.

atmospheric tides

since time of laplace (1799), scientists had been puzzled why pressure variations measured @ earth s surface associated semi-diurnal solar tide dominate of diurnal tide in amplitude, when intuitively 1 expect diurnal (daily) passage of sun dominate. lord kelvin (1882) had proposed so-called resonance theory, wherein semi-diurnal tide selected on diurnal oscillation if atmosphere somehow able oscillate freely @ period of close 12 hours, in same way overtones selected on vibrating string. second half of twentieth century, however, observations had failed confirm hypothesis, , alternative hypothesis proposed must instead suppress diurnal tide. in 1961, manfred siebert suggested absorption of solar insolation tropospheric water vapour might account reduction of diurnal tide. however, failed include role stratospheric ozone. rectified in 1963 australian physicist stuart thomas butler , student k.a. small showed stratospheric ozone absorbs greater part of solar insolation.

nevertheless, predictions of classical tidal theory still did not agree observations. lindzen, in 1966 paper, on theory of diurnal tide, showed solution set of hough functions given bernard haurwitz laplace s tidal equation incomplete: modes negative equivalent depths had been omitted. lindzen went on calculate thermal response of diurnal tide ozone , water vapor absorption in detail , showed when theoretical developments included, surface pressure oscillation predicted approximately magnitude , phase observed, of features of diurnal wind oscillations in mesosphere. in 1967, along ncar colleague, douglas d. mckenzie, lindzen extended theory include term newtonian cooling due emission of infrared radiation carbon dioxide in stratosphere along ozone photochemical processes, , in 1968 showed theory predicted semi-diurnal oscillation insensitive variations in temperature profile, why observed more , regularly @ surface.

while holding position of research scientist @ national center atmospheric research (ncar) in boulder, co lindzen noticed , befriended professor sydney chapman, had contributed theory of atmospheric tides in number of papers 1920s through 1940s. led joint publication in 1969 of 186-page monograph (republished in 1970 book) atmospheric tides.

quasi-biennial oscillation

although wasn t realized @ time, quasi-biennial oscillation (qbo) observed during 1883 eruption of krakatoa, when ash volcano transported around globe east west stratospheric winds in 2 weeks. these winds became known krakatoa easterlies . observed again in 1908, german meteorologist arthur berson, saw winds blow west @ 15 km (9.32 mi) altitude in tropical africa balloon experiments. these became known berson westerlies . however, not until 1960s ~ 26-month cycle of qbo first described, independently richard j. reed in 1960 , veryhard , ebdon in 1961.

lindzen recalls discovery of mechanism underlying qbo in semi-autobiographical review article, on development of theory of qbo. interest in phenomenon began in 1961 when phd advisor, richard m. goody, speculated 26-month relaxation time stratospheric ozone @ 25 km (15.53 mi) in tropics might somehow related 26-month period of qbo, , suggested investigation of idea thesis topic. in fact, lindzen s, radiative , photochemical processes in mesospheric dynamics, part ii: vertical propagation of long period disturbances @ equator, documented failure of attempt explain qbo.

lindzen s work on atmospheric tides led him study of planetary waves , general circulation of atmospheres. 1967, had contributed number of papers on theory of waves in middle atmosphere. in planetary waves on beta planes, developed beta plane approximation simplifying equations of classical tidal theory, whilst @ same time developing planetary wave relations. noticed equations eastward-traveling waves (known rossby waves since discovery in 1939 carl-gustav rossby) , westward-traveling waves (which lindzen himself helped in establishing atmospheric kelvin waves ) periods less 5 days vertically trapped. @ same time, important paper booker , bretherton appeared, lindzen read great interest. booker , bretherton showed vertically propagating gravity waves absorbed @ critical level.

in 1968 paper james r. holton, theory of quasi-biennial oscillation, lindzen presented theory of qbo after testing in two-dimensional (2-d) numerical model had been developed holton , john m. wallace. showed qbo driven vertically propagating gravity waves phase speeds in both westward , eastward directions , oscillation arose through mechanism involving two-way feedback between waves , mean flow. bold conjecture, given there little observational evidence available either confirm or confute hypothesis. in particular, there still no observational evidence of westward-traveling kelvin waves; lindzen postulated existence theoretically.

in years following publication of lindzen , holton (1968), more observational evidence became available, , lindzen s fundamental insight mechanism driving qbo confirmed. however, theory of interaction via critical level absorption found incomplete , modified include importance of attenuation due radiative cooling. revised theory published in holton , lindzen (1972) paper, updated theory quasibiennial cycle of tropical stratosphere.

superrotation of venus

since 1960s puzzling phenomenon has been observed in atmosphere of venus. atmosphere above cloud base seen travel around planet 50 times faster rotation of planet surface, or in 4 5 earth-days. in 1974 theory proposed stephen b. fels , lindzen explain so-called superrotation held rotation driven thermal atmospheric tide. alternative theory proposed peter j. gierasch in following year held instead meridional (hadley) circulation may transport momentum eddy-mixing. actual cause of phenomenon continues debated in literature, general circulation model experiments suggesting both fels/lindzen , gierasch mechanisms involved.

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