Predicting the polarization of the microwave background from the WMAP temperature maps     

A. H. Jaffe 《New Astronomy Reviews》2003,47(11-12):1001

In this paper, we study how to predict the polarization of the Cosmic Microwave Background (CMB) using knowledge of only the temperature (intensity) and the cross-correlation between temperature and polarization. We derive a “Wiener prediction” method and apply it to the Wilkinson Microwave Anisotropy Probe (WMAP) all-sky CMB temperature maps and to the MAXIMA field.  相似文献   

MAXIPOL: a balloon-borne experiment for measuring the polarization anisotropy of the cosmic microwave background radiation     

B. R. Johnson  M. E. Abroe  P. Ade  J. Bock  J. Borrill  J. S. Collins  P. Ferreira  S. Hanany  A. H. Jaffe  T. Jones  A. T. Lee  L. Levinson  T. Matsumura  B. Rabii  T. Renbarger  P. L. Richards  G. F. Smoot  R. Stompor  H. T. Tran  C. D. Winant 《New Astronomy Reviews》2003,47(11-12):1067

We discuss MAXIPOL, a bolometric balloon-borne experiment designed to measure the E-mode polarization anisotropy of the cosmic microwave background radiation (CMB) on angular scales of 10^′ to 2°. MAXIPOL is the first CMB experiment to collect data with a polarimeter that utilizes a rotating half-wave plate and fixed wire-grid polarizer. We present the instrument design, elaborate on the polarimeter strategy and show the instrument performance during flight with some time domain data. Our primary dataset was collected during a 26 h turnaround flight that was launched from the National Scientific Ballooning Facility in Ft. Sumner, New Mexico in May 2003. During this flight five regions of the sky were mapped. Data analysis is in progress.  相似文献   

Three-dimensional swimming behavior of individual zooplankters: observations using the acoustical imaging system FishTV     

McGehee  Duncan; Jaffe  Jules S. 《ICES Journal of Marine Science》1996,53(2):363-369

  相似文献   

Accelerated relative sea-level rise and rapid coastal erosion:: testing a causal relationship for the Louisiana barrier islands   总被引：1，自引：0，他引：1  

Jeffrey H. List  Asbury H. Sallenger Jr.  Mark E. Hansen  Bruce E. Jaffe 《Marine Geology》1997,140(3-4):347-365

The role of relative sea-level rise as a cause for the rapid erosion of Louisiana's barrier island coast is investigated through a numerical implementation of a modified Bruun rule that accounts for the low percentage of sand-sized sediment in the eroding Louisiana shoreface. Shore-normal profiles from 150 km of coastline west of the Mississippi delta are derived from bathymetric surveys conducted during the 1880s, 1930s and 1980s. An RMS difference criterion is employed to test whether an equilibrium profile form is maintained between survey years. Only about half the studied profiles meet the equilibrium criterion; this represents a significant limitation on the potential applicability of the Bruun rule. The profiles meeting the equilibrium criterion, along with measured rates of relative sea-level rise, are used to hindcast shoreline retreat rates at 37 locations within the study area. Modeled and observed shoreline retreat rates show no significant correlation. Thus, in terms of the Bruun approach, relative sea-level rise has no power for hindcasting (and presumably forecasting) rates of coastal erosion for the Louisiana barrier islands.  相似文献   

Science aspects of a mission beyond the planets     

Leonard D. Jaffe  Charles V. Ivie 《Icarus》1979,39(3):486-494

A mission out of the planetary system, launched about the year 2000, could provide valuable data concerning characteristics of the heliopause, the interstellar medium, stellar distances (by parallax measurements), low-energy cosmic rays, interplanetary gas distribution, and mass of the solar system. Secondary objectives include investigation of Pluto. Candidate science measurements, instruments, and instrument development needs are discussed. The mission should extend from 400 to 1000 AU from the Sun. A heliocentric hyperbolic escape velocity of 50–100 km/sec or more is needed to attain this distance within a reasonable mission duration (20–50 years). The trajectory should be toward the incoming interstellar gas. For a year 2000 launch, a Pluto encounter and orbiter can be included. A second mission targeted parallel to the solar axis would also be worthwhile.  相似文献   

Reservoirs of atmospheric chlorine: Prospects for HOCl revisted     

S.S. Prasad  R.L. Jaffe  R.C. Whitten  R.P. Turco 《Planetary and Space Science》1978,26(11):1017-1026

We have re-examined the prospects of HOCl as an inert reservoir for atmospheric chlorine in the light of new theoretical calculations and available experimental measurements of its photodissociation cross-sections. The theoretical calculations and most recent laboratory studies imply that the broad maxima 3200 Å observed in two other experimental spectra may not belong to HOCl. On the basis of this implication HOCl could have a long lifetime against photodissociation in the stratosphere, and could, thereby, become a reservoir for atmospheric chlorine comparable to ClONO₂ or even HCl. In this capacity HOCl could reduce the predicted ozone destruction due to any given level of total chlorine burden. We have also examined the difficulties in laboratory measurements of the HOCl absorption spectrum with particular emphasis on identifying the impurities which may be present in the experimental system. It appears that specialized new experiments are needed to clearly establish the nature and strength of HOCl absorption in the neighbourhood of 3200 Å. Some refinements in the theoretical calculations also seem desirable. In view of the difficulties involved in the laboratory determination of HOCl photodissociation cross-sections, it is suggested that a search for possible stratospheric HOCl by atmospheric spectroscopists would be worthwhile.  相似文献   

Reactive Nitrogen Compounds at Spitsbergen in the Norwegian Arctic     

S. Solberg  T. Krognes  F. Stordal  OØ Hov  H. J. Beine  D. A. Jaffe  K. C. Clemitshaw  S. A. Penkett 《Journal of Atmospheric Chemistry》1997,28(1-3):209-225

Simultaneousindependent measurements of NO_y and NO_x(NO_x= NO + NO₂) by high-sensitivitychemiluminescence systems and of PAN (peroxyacetylnitrate) and PPN (peroxypropionyl nitrate) by GC-ECDwere made at Spitsbergen in the Norwegian Arcticduring the first half year of 1994. The average mixingratio of the sum of PAN and PPN (denoted PANs)increased from around 150 pptv in early winter to amaximum of around 500 pptv in late March, whereasepisodic peak values reached 800 pptv. This occurredsimultaneously with a maximum in ozone which increasedto 45–50 ppbv in March–April. The average NO_xmixing ratio was 27 pptv and did not show any cyclethrough the period. The NO_y mixing ratio showeda maximum in late March, while the difference betweenNO_y and PAN decreased during spring. This is anindication of the dominance of PAN in the NO_ybudget in the Arctic, but possible changes in theefficiency of the NO_y converter could alsocontribute to this. Although most PAN in theArctic is believed to be due to long range transport,the observations indicate local loss and formationrates of up to 1–2 pptv h^-1 in April–May.Measurements of carbonyl compounds suggest thatacetaldehyde was the dominant, local precursor ofPAN.Now at 1.  相似文献   

Equilibrium coexistence of three amphiboles     

Peter Robinson  Howard W. Jaffe  Cornelis Klein Jr.  Malcolm Ross 《Contributions to Mineralogy and Petrology》1969,22(3):248-258

Electron probe and wet chemical analyses of amphibole pairs from the sillimanite zone of central Massachusetts and adjacent New Hampshire indicated that for a particular metamorphic grade there should be a restricted composition range in which three amphiboles can coexist stably. An unequivocal example of such an equilibrium three amphibole rock has been found in the sillimanite-orthoclase zone. It contains a colorless primitive clinoamphibole, space group P2₁/m, optically and chemically like cummingtonite with blue-green hornblende exsolution lamellae on (100) and (¯101) of the host; blue-green hornblende, space group C2/m, with primitive cummingtonite exsolution lamellae on (100) and (¯101) of the host; and pale pinkish tan anthophyllite, space group Pnma, that is free of visible exsolution lamellae but is a submicroscopic intergrowth of two orthorhombic amphiboles. Mutual contacts and coarse, oriented intergrowths of two and three host amphiboles indicate the three grew as an equilibrium assemblage prior to exsolution. Electron probe analyses at mutual three-amphibole contacts showed little variation in the composition of each amphibole. Analyses believed to represent most closely the primary amphibole compositions gave atomic proportions on the basis of 23 oxygens per formula unit as follows: for primitive cummingtonite (Na_0.02Ca_0.21 ^– Mn_0.06Fe²⁺ _2.28Mg_4.12Al_0.28) (Al_0.17Si_7.83), for hornblende (Na_0.35Ca_1.56Mn_0.02Fe_1.71Mg_2.85Al_0.92) (Al_1.37Si_6.63), and for anthophyllite (Na_0.10Ca_0.06Mn_0.06Fe_2.25Mg_4.11Al_0.47) (Al_0.47Si_7.53). The reflections violating C-symmetry, on X-ray single crystal photographs of the primitive cummingtonite, are weak and diffuse, and suggest a partial inversion from a C-centered to a primitive clinoamphibole. Single crystal photographs of the anthophyllite show split reflections indicating it is an intergrowth of about 80% anthophyllite and about 20% gedrite which differ in their b crystallographic dimensions. Split reflections are characteristic of all analyzed orthorhombic amphiboles so far examined from Massachusetts and New Hampshire except the most aluminous gedrites, and the relative intensity of the gedrite reflections is roughly proportional to the degree of Na and Al substitution. Thin sections of a few of these anthophyllite specimens show lamellae parallel to (010) that are just resolved with a high power objective.Publication approved by the Director, U.S. Geological Survey.  相似文献   

A Measurement of Omega from the North American Test Flight of Boomerang     

Melchiorri A  Ade PA  de Bernardis P  Bock JJ  Borrill J  Boscaleri A  Crill BP  De Troia G  Farese P  Ferreira PG  Ganga K  de Gasperis G  Giacometti M  Hristov VV  Jaffe AH  Lange AE  Masi S  Mauskopf PD  Miglio L  Netterfield CB  Pascale E  Piacentini F  Romeo G  Ruhl JE  Vittorio N 《The Astrophysical journal》2000,536(2):L63-L66

We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85相似文献   

Physical criteria for distinguishing sandy tsunami and storm deposits using modern examples   总被引：4，自引：0，他引：4  

Robert A. Morton  Guy Gelfenbaum  Bruce E. Jaffe 《Sedimentary Geology》2007,200(3-4):184-207

Modern subaerial sand beds deposited by major tsunamis and hurricanes were compared at trench, transect, and sub-regional spatial scales to evaluate which attributes are most useful for distinguishing the two types of deposits. Physical criteria that may be diagnostic include: sediment composition, textures and grading, types and organization of stratification, thickness, geometry, and landscape conformity.

Published reports of Pacific Ocean tsunami impacts and our field observations suggest that sandy tsunami deposits are generally < 25 cm thick, extend hundreds of meters inland from the beach, and fill microtopography but generally conform to the antecedent landscape. They commonly are a single homogeneous bed that is normally graded overall, or that consists of only a few thin layers. Mud intraclasts and mud laminae within the deposit are strong evidence of tsunami deposition. Twig orientation or other indicators of return flow during bed aggradation are also diagnostic of tsunami deposits. Sandy storm deposits tend to be > 30 cm thick, generally extend < 300 m from the beach, and will not advance beyond the antecedent macrotopography they are able to fill. They typically are composed of numerous subhorizontal planar laminae organized into multiple laminasets that are normally or inversely graded, they do not contain internal mud laminae and rarely contain mud intraclasts. Application of these distinguishing characteristics depends on their preservation potential and any deposit modifications that accompany burial.

The distinctions between tsunami and storm deposits are related to differences in the hydrodynamics and sediment-sorting processes during transport. Tsunami deposition results from a few high-velocity, long-period waves that entrain sediment from the shoreface, beach, and landward erosion zone. Tsunamis can have flow depths greater than 10 m, transport sediment primarily in suspension, and distribute the load over a broad region where sediment falls out of suspension when flow decelerates. In contrast, storm inundation generally is gradual and prolonged, consisting of many waves that erode beaches and dunes with no significant overland return flow until after the main flooding. Storm flow depths are commonly < 3 m, sediment is transported primarily as bed load by traction, and the load is deposited within a zone relatively close to the beach.  相似文献