Nutrient load estimates for Manila Bay,Philippines using population data

A major source of nutrient load to periodically hypoxic Manila Bay is the urban nutrient waste water flow from humans and industries to surface water. In Manila alone, the population density is as high as 19,137 people/km². A model based on a global point source model by Morée et al. (2013) was used to estimate the contribution of the population to nitrogen and phosphorus emissions which was then used in a water transport model to estimate the nitrogen (N) and phosphorus (P) loads to Manila Bay. Seven scenarios for 2050 were tested, with varying degrees and amounts for extent of sewage treatment, and population growth rates were also included. In scenario 1, the sewage connection and treatment remains the same as 2010; in scenario 2, sewage connection is improved but the treatment is the same; in scenario 3, the sewage connection as well as treatment is improved (70% tertiary); and in scenario 4, a more realistic situation of 70% primary treatment achieved with 100% connection to pipes is tested. Scenarios 5, 6, and 7 have the same parameters as 1, 2, and 3 respectively, but with the population growth rate per province reduced to half of what was used in 1, 2, and 3. In all scenarios, a significant increase in N and P loads was observed (varying from 27% to 469% relative to 2010 values). This was found even in scenario 3 where 70% of the waste water undergoes tertiary treatment which removes 80% N and 90% P. However, the lowest increase in N and P load into the bay was achieved in scenarios 5 to 7 where population growth rate is reduced to half of 2010 values. The results suggest that aside from improving sewage treatment, the continued increase of the human population in Manila at current growth rates will be an important determinant of N and P load into Manila Bay.

     

CLASSIFICATION OF A SECOND GROUP OF ORDINARY CHONDRITES FROM TEXAS

Based on optical microscopy and electron microprobe analyses of mafic minerals, six previously undescribed or poorly known ordinary chondrites from Texas were classified into compositional groups, petrologic types, and shock facies. These meteorites are Junction, L5d; Anton, H4b; Venus, H4d; Dalhart, H5a; Rosebud, H5c; and Cranfills Gap, H6c.     

Motions and mass changes of a persistent coronal streamer

A coronal streamer was observed by the white light coronagraph on Skylab during 5 successive limb passages between 1 June, 1973 and 6 August, 1973. The Skylab data give independent measures of coronal brightness and polarization, as functions of time. These permit the distinction between changes in the coronal streamer's appearance due to solar rotation and actual structural changes. The streamer's visual appearance changed slightly between successive limb passages indicating that it was not a steady state feature. Measurements of the streamer's latitude, brightness, and polarization during 3 east limb passages show that: (1) the streamer's axis migrated southward from 25° N at first east limb passage to 11° N at second east limb passage to 8° N latitude at third east limb passage; (2) the streamer's mass (and mass gradient with height), varied by between 20 and 50% from one east limb passage to the next; (3) the streamer's longitudinal extent was also observed to be less on successive east limb passages; and (4) mass changes (distinct from coronal transients) occurring over hours were detected during at least two limb passages. Comparison of the outer coronal observations with observations from lower in the solar atmosphere indicate that the streamer was associated with a complex of solar activity consisting of active regions and filaments. This complex of activity shifted southward by the same amount as the streamer. The variations detected in the streamer preclude the detailed determination of its three-dimensional structure.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

Generation of lateral and rotational floor response spectra by an alternative approach

A procedure is described to compute the lateral and rotational floor response spectra of an asymmetric reactor building structure without a time history analysis. The spectral values obtained by filtering the prescribed ground motion first through the structure and the resulting lateral-rotational motions through simple oscillators are equal to the maximum lateral-rotational responses of the structure developed when the order of filtration is reversed. Based on the preceding concept a deterministic method is presented to construct the lateral-rotational floor response spectra utilizing the response spectrum technique.     

Low salinity residual ballast discharge and exotic species introductions to the North American Great Lakes

Exotic species introductions to the North American Great Lakes have continued even though ballast water management strategies were implemented in the early 1990s. Overseas vessels that arrive with little or no exchangeable ballast on board have been suspected to be an important source for discharging low salinity ballast containing low salinity tolerant organisms in this region. Residual ballast averaged 18.1+/-13.4 per thousand salinity among 62 samples taken primarily from bottom tanks on 26 vessels that entered the Great Lakes in 1999 and 2000. Sampling of 2-4 tanks each on nine vessels indicated all carried at least one tank of residual ballast of 相似文献   

Loss of nutrients from catchments and their ecological impacts in the Peel-Harvey estuarine system,Western Australia

Rivers draining coastal-plain soils with a low phosphorus-binding capacity load nutrients into the estuarine system in winter. Phosphorus is largely trapped by diatom blooms and recycled via the sediments to support growth, during the warmer months, of blue-green algae in Harvey Estuary or macroalgae in Peel Inlet. The magnitude of blue-green algae (Nodularia) blooms is related to the amount of river water entering in winter; blooms collapse as salinities rise toward that of the ocean. For macroalgae the relationship between light and nutrient availability is of critical importance. Control measures are concerned with reducing phosphorus loads from catchments and increasing water exchange with the ocean through the proposed construction of a new channel.     

Diagnosis of the satellite-observed radiative heating in relation to the summer monsoon

Seasonal and monthly global patterns of outgoing longwave radiation, albedo, absorbed solar radiation, and net radiation have been derived from scanning radiometer observations aboard the NOAA polar orbiting satellites since June 1974. These patterns, along with patterns of interannual differences in seasonal and monthly heating, are examined for the three summers of 1974–76 over the Eastern Hemisphere in relation to the variations in the summer monsoon and the major circulation features. During portions of the summer of 1975 the monsoon was more active than in 1974 and 1976, as evidenced by increased albedo and decreased longwave radiation over large sections of India, the Indian Ocean, Southeast Asia, and the Western Pacific. The roles of clouds, snow cover, and other surface characteristics in modulating the radiation balance and circulation are discussed. The pre-monsoon radiative heating in spring is examined with respect to monsoon onset and intensity in the three years.     

Observations of contemporary arroyo cutting near Santa Fe,New Mexico,U.S.A.

Arroyo cutting that began in the American Southwest in the 1880s is associated with sudden runoff, a circumstance characteristic of this semiarid region in which occasional intense rainfall exceeds the capacity of the ground to absorb water. This report describes two arroyos in an area of moderately dissected bolson deposits southwest of Santa Fe, Cañada de la Cueva and Pueblo Cañon, where arroyo cutting since 1970 has been closely related to runoff from summer rain. The area is vegetated chiefly by grama grass and scattered juniper. Cutting is monitored by repeated surveys of channel floors, cross-sections, and headcuts, and by repeated photographs taken as stereopairs. Rainfall and discharge are measured simultaneously in 5-minute intervals by dual digital recorders at a gauging station on Cañada de la Cueva (drainage area 4.64 km²). Discharge has been as much as 18.2 m³/s from rainfall of 25.2 mm. The maximum 15-minute intensity for this storm was 64.0 mm/hr, and runoff was 7.9 mm. The flood peak arrived in 20 minutes, by which time 80 per cent of the rain had fallen, and the flow subsided to a tenth of its maximum in less than an hour. This storm at Pueblo Cañon (drainage area 13.3 km² above the place of measurement) resulted in an estimated discharge of 140 m³/s, and features produced by hail on the channel floor suggest that the duration of flow could have been as brief as 30 minutes. Observed increments of headward cutting at Cañada de la Cueva range from 0.28 m for 1.8 mm of runoff to 4.9 m for 12 mm of runoff. Aggregate cutting in 5 years has been as much as 13.7 m, resulting in erosion of 570 m³ of alluvium. Headward cutting near the mouth of Pueblo Cañon has been observed in increments of 10.3, 14.6, and 20.7 m, for an aggregate of 45.6 m, as measured from 1971 to 1974. This cutting removed 1,770 m³ of alluvium.     

THE USE OF POLYNOMIALS FOR ADJUSTING STRIPS TO CONTROL

The following article and correspondence have been reproduced from 'The Photogrammetric Review,' the journal of the Ordnance Survey Photogrammetric Society, by permission of the editor, as it is relevant to the paper by Professor Thompson, published in 'The Photogrammetric Record,' Vol. 1, No. 1, of March , 1953.