In this thesis, we have presented a systematic analysis of the change of cloud properties due to variation in aerosol concentration over Indian region using satellite observations, and Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) simulations. The Tropical Rainfall Measurement Mission (TRMM) based Microwave Imager (TMI) estimates (2A12) have been used to compare and contrast the characteristics of cloud liquid water and ice over the Indian land region and the surrounding oceans, during the pre-monsoon (May) and monsoon (June–September) seasons. Based on the spatial homogeneity of rainfall, we have selected five regions for our study (three over ocean, two over land). In general, we find that the mean cloud liquid water and cloud ice content of land and oceanic regions are different, with the ocean regions showing higher amount of CLW. A comparison across the ocean regions suggests that the cloud liquid water over the or graphically influenced Arabian Sea (close to the Indian west coast) behaves differently from the cloud liquid water over a trapped ocean (Bay of Bengal) or an open ocean (Equatorial Indian Ocean). Specifically, the Arabian Sea region shows higher liquid water for a lower range of rainfall, whereas the Bay of Bengal and the Equatorial Indian Ocean show higher liquid water for a higher range of rainfall. Apart from geographic differences, we also documented seasonal differences by comparing cloud liquid water profiles between monsoon and pre-monsoon periods, as well as between early and peak phases of the monsoon. We find that the cloud liquid water during the lean periods of rainfall (May or June) is higher than during the peak and late monsoon season (July-September) for raining clouds over central India. However, this is not true over the ocean. As active and break phases are important signatures of the monsoon progression, we also analyzed the differences in cloud liquid water during various phases of the monsoon, namely, active, break, active-to-break (a2b) and break-to-active (b2a) transition phases. We find that the cloud liquid water content during the b2a transition phase is significantly higher than that during the a2b transition phase over central India. We speculate that this could be attributed to higher amount of aerosol loading over this region during the break phase. We lend credence to this aerosol-liquid water/rain association by comparing the central Indian cloud liquid water with Southeast Asia (where the aerosol loading is significantly smaller) and find that in the latter region, there are no significant differences in cloud liquid water during the different phases of their monsoon. The second part of our study involves evaluating the ability of the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) to simulate the observed variation of cloud liquid water and rain efficiency. We have used no chemistry option, and the model was run with constant aerosol concentration. The model simulations (at 4.5 km resolution) are done for the month of June–July 2004 since this period was particularly favorable for the study of an active–break cycle of the monsoon. We first evaluate the sensitivity of the model to different parameterizations (microphysical, boundary layer, land surface) on the simulation of rain over central India and Bay of Bengal. This is done to identify an “optimal” combination of parameterizations which reproduces the best correlation with observed rain over these regions. In this default configuration (control run), where the aerosol concentration is kept constant throughout the simulation period, the model is not able to reproduce the observed variations of cloud liquid water during the different phases of an active-break cycle. To this end, we proceeded to modify the model by developing an aerosol-rain relation, using Aerosol Robotic Network (AERONET) and TRMM 3B42 data that realistically captures the variation of aerosol with rain. It is worth highlighting here that our goal was to primarily isolate the indirect effect of aerosols in determining the observed changes in cloud liquid water (CLW) during the active-break phases of the Indian monsoon, without getting into the complexity of a full chemistry model such as that incorporated in WRF-Chem. Moreover, the proposed modification (modified run) is necessitated by the lack of realistic emission estimates over the Indian region as well as the presence of inherent biases in monsoon simulation in WRF. The main differences we find between the modified and control simulations is in the mean as well as spatial variability of CLW. We find that the proposed modification (i.e., rate of change of aerosol concentration as a function of rain rate) leads to a realistic variation in the CLW during the active-break cycle of Indian monsoon. Specifically, the peak value of CLW in the b2a (a2b) phase is larger (smaller) in the modified as compared to the control run. These results indicate a stronger change in CLW amount in the upper levels between the two transition phases in the modified scheme as compared to the control simulation. More significantly, we also observe a change in sign at the lower levels of the atmosphere, i.e., from a strong positive difference in the control run to a negative difference in the modified simulation, similar to that observed. Additionally, we investigated the impact of the proposed modification, via CLW changes, on cloud coverage, size of clouds and their spatial variability. We find that the transformation of optically thin clouds to thick clouds during the break phase was associated with larger cloud size in modified compared to the control simulation. Moreover, the higher rate of decay of the spatial variability of CLW with grid resolution, using the modified scheme, suggests that clusters of larger clouds are more in the modified compared to control simulation. Taken together, the interactive aerosol loading proposed in this thesis yields model simulations that better mimic the observed CLW variability between the transition phases.

För att vatten ska kunna levereras enligt de krav som ställs från användarna i samhället behövs ett väl anpassat ledningsnät. Det innebär bland annat att vatten ska finnas tillgängligt i den mängd som behövs och vid den tidpunkt som vatten krävs. För att vattenreningsverken ska kunna leverera rätt mängd vatten måste ledningsnätet vara dimensionerat för att kunna transportera allt vatten som skall pumpas ut till användarna. Detta kräver en god uppskattning om de vattenflöden som behövs. Det förväntade vattenflödet till olika samhällsanvändare uppskattas utifrån befintliga användningsmönster samt publikation P83, framtagen av Svenskt Vatten. Allt eftersom samhället utvecklas behöver publikationen uppdateras för att denna ska stämma så väl överens med verkligheten som möjligt. Vattenanvändningsmönster i skolor, kontor, handelsområden och industrier undersöktes som en del av ett pågående projekt för att undersöka om P83 bör uppdateras. För dessa har år- och dygnsvariationer, flöden och maxfaktorer analyserats från årslånga mätserier. Utifrån uppmätta värden kunde alternativa fördelningsnycklar som potentiellt skulle bidra till förbättring också analyseras. Resultaten tyder på att det finns förbättringsmöjligheter för flödesberäkningar för brukartyperna skolor, handel och industri jämfört med dagens metoder. För skolor och handel skulle inomhusarea vara en relevant fördelningsnyckel att använda vid beräkningar medan takyta vore en mer lämplig parameter att använda för industrier. De maxfaktorer som finns angivna i P83 stämde inte särskilt väl överens med de uppmätta i studien och skulle behöva uppdateras. Studien visar också på ett behov av att dela upp de brukarkategorier som finns i dagsläget till fler kategorier då de tre som finns i dagsläget är mycket generella. Dessutom undersöktes möjligheten att kombinera olika brukartyper för att utjämna vattenflöden under dygnet. Villor eller radhus bör lämpligen kombineras med skolor, kontor eller industrier för att få ett jämnare vattenflöde under dagtid. / For water to be delivered according to the requirements of the users in the society there is a need for the water pipelines to be well dimensioned. This means that the amount of water that is needed has to be available at the time when it is required. For the water treatment plants to be able to deliver the right amount of water the pipelines must be sized to carry the water that should be delivered to the users. This requires a good estimate of the amount of water needed. The expected water flow to different users is estimated based on existing water usage patterns as well as the P83 publication, developed by Swedish Water. As society develops the publication may need to be updated to correspond well with reality. Water use patterns in schools, offices, retail stores and industries were examined as a part of an ongoing project to investigate whether P83 should be updated. For these annual and diurnal variations, water flows and max factors were analyzed from yearlong series of measurements. Based on the measured values alternate allocation keys that could potentially contribute to improvement were analyzed. The results suggest that there are possible improvements for flow calculations for schools, retail stores and industry compared to current methods. For schools and retail stores the indoor area would be a relevant variable to use for calculations, while the roof area would be a more appropriate variable to use for industries. The max factors listed in P83 did not agree with those measured in the study and would need to be updated. The study shows that the three categories used in P83 are very general and ought to be divided into more specific categories. Furthermore, the possibility to combine different types of water users to equalize the water flow to an area during the day was analyzed. Villas or semi-attached houses should preferably be combined with schools, offices or industries for evening out the flow during day time.

Hyperspectral imaging has become one of the most popular technologies in plant phenotyping because it can efficiently and accurately predict numerous plant physiological features such as plant biomass, leaf moisture content, and chlorophyll content. Various hyperspectral imaging systems have been deployed in both greenhouse and field phenotyping activities. However, the hyperspectral imaging quality is severely affected by the continuously changing environmental conditions such as cloud cover, temperature and wind speed that induce noise in plant spectral data. Eliminating these environmental effects to improve imaging quality is critically important. In this thesis, two approaches were taken to address the imaging noise issue in greenhouse and field separately. First, a computational simulation model was built to simulate the greenhouse microclimate changes (such as the temperature and radiation distributions) through a 24-hour cycle in a research greenhouse. The simulated results were used to optimize the movement of an automated conveyor in the greenhouse: the plants were shuffled with the conveyor system with optimized frequency and distance to provide uniform growing conditions such as temperature and lighting intensity for each individual plant. The results showed the variance of the plants’ phenotyping feature measurements decreased significantly (i.e., by up to 83% in plant canopy size) in this conveyor greenhouse. Secondly, the environmental effects (i.e., sun radiation) on <a>aerial </a>hyperspectral images in field plant phenotyping were investigated and modeled. <a>An artificial neural network (ANN) method was proposed to model the relationship between the image variation and environmental changes. Before the 2019 field test, a gantry system was designed and constructed to repeatedly collect time-series hyperspectral images with 2.5 minutes intervals of the corn plants under varying environmental conditions, which included sun radiation, solar zenith angle, diurnal time, humidity, temperature and wind speed. Over 8,000 hyperspectral images of </a>corn (<i>Zea mays </i>L.) were collected with synchronized environmental data throughout the 2019 growing season. The models trained with the proposed ANN method were able to accurately predict the variations in imaging results (i.e., 82.3% for NDVI) caused by the changing environments. Thus, the ANN method can be used by remote sensing professionals to adjust or correct raw imaging data for changing environments to improve plant characterization.

Thesis (Ph.D.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and the Woods Hole Oceanographic Institution), 2000. / Includes bibliographical references (p. 217-222). / Estimation of the upper ocean heat budget from one year of observations at a moored array in the north central Arabian Sea shows a rough balance between the horizontal advection and time change in heat when the one-dimensional balance between the surface heat flux and oceanic heat content breaks down. The two major episodes of horizontal advection, during the early northeast (NE) and late southwest (SW) monsoon seasons, are both associated with the propagation of mesoscale eddies. During the NE monsoon, the heat fluxes within the mixed layer are not significantly different from zero, and the large heat flux comes from advected changes in the thermocline depth. During the SW monsoon a coastal filament exports recently upwelled water from the Omani coast to the site of the array, 600 km offshore. Altimetry shows mildly elevated levels of surface eddy kinetic energy along the Arabian coast during the SW monsoon, suggesting that such offshore transport may be an important component of the Arabian Sea heat budget. The sea surface temperature (SST) and mixed layer depth are observed to respond to high frequency (HF, diurnal to atmospheric synoptic time scales) variability in the surface heat flux and wind stress. The rectified effect of this HF forcing is investigated in a three-dimensional reduced gravity thermodynamic model of the Arabian Sea and Indian Ocean. Both the HF heat and wind forcing act locally to increase vertical mixing in the model, reducing the SST. Interactions between the local response to the surface forcing, Ekman divergences, and remotely propagated signals in the model can reverse this, generating greater SSTs under HF forcing, particularly at low latitudes. The annual mean SST, however, is lowered under HF forcing, changing the balance between the net surface heat flux (which is dependent on the SST) and the meridional heat flux in the model. A suite of experiments with one-dimensional upper ocean models with different representations of vertical mixing processes suggests that the rectified effect of the diurnal heating cycle is dependent on the model, and overstated in the formulation used in the three-dimensional model. / by Albert Sok Fischer. / Ph.D.

Maintaining dissolved oxygen concentrations under different operating schemes (constant, manual or automated aeration control) was evaluated in 20 earthen catfish ponds ranging from 0.04 to 0.07 hectares in size. Ponds were assigned to treatments based on achieving equal distribution of biomass among treatments. Catfish weighing approximately 0.11 kg each were stocked at a rate of 14,820 catfish/hectare and were fed, to satiation, a 36% crude protein floating feed for the first week and switched to a 32% crude protein floating feed for the remainder of the study. Percentage weight gain, FCR and survival were calculated but did not differ among treatments. A partial enterprise budget analysis was generated to determine comparative value of different aeration techniques relative to production costs. Mean partial net returns did not differ among treatments. Complete comparison was not possible due to failure of automated monitors to record DO and to operate aerators under designed protocols.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Transpiration rates (T) of riparian phreatophytes can be high. Antitranspirant (AT) sprays can curtail T without the ecological imbalance made by eradication. Saltcedar (Tamarix sp.) and cottonwood (Populus sp.) in 15-gal. drums enabled replicated trials on isolated plants or on canopies. T of isolate saltcedar plants could be 2x that of plants in a fairly dense canopy. T for a unit ground area of saltcedar varied from 2.2 (sparse -) to 15.8 (dense-stand) mm/day in July at Davis. Extrapolation of experimental T data to field sites must, therefore, be made carefully. Wax -based ATs increased foliar diffusive resistance (R), and reduced T of saltcedar and cottonwood 32-38% initially and 10% after 3 weeks. R increased naturally in the afternoon when evaporative demand was high and if soil water was low. Nocturnal T of salt cedar was 10% of day T. AT effectiveness increased with a higher ratio of day: night hours, and with lower soil water stress. Therefore, AT will be most effective on long summer days in riparian areas where ground water is available.

科学研究費補助金 研究種目:基盤研究(B)(2) 課題番号:08458144 研究代表者:飯田 孝夫 研究期間:1996-1997年度

The main aim of this research is to improve our knowledge of the sea breeze circulation in the complex coastal environments, where more than one mesoscale circulations occur. Interaction of these circulations with each other and with external factors such as topographical features and large scale winds leads to pronounced changes in the thermodynamic structure of the boundary layer. The variations in sea breeze circulation also have distinct effect on the pollutant transport and dispersion mechanisms in the coastal urban areas. In this research, dynamic and thermodynamic characteristics of the sea breeze circulation and their associated air pollution potential have been investigated by utilizing observational data for two summer periods and numerical modelling techniques. Effect of some external factors such as gradient flow and terrain elevation has also been examined. Observed meteorological and air quality data was obtained from a number of monitoring sites within and around Auckland while Advanced Weather Research & Forecasting (WRF) and ‘The Air Pollution Model’ (TAPM) were employed to simulate meteorology and pollutant dispersion in Auckland. WRF is used to investigate the thermally induced mesoscale circulation while TAPM has been employed to examine the pollutant dispersion in the region. Both models were validated against observed data from six different sites within Auckland. Validation results of WRF and TAPM are also compared with surface meteorology. Validation and inter-comparison of the two models show that WRF performed better than TAPM for all the surface meteorology variables. WRF showed a positive bias in predicted winds speed and relative humidity and a cold bias in the near surface Temperature. TAPM on the other hand under-predicted surface winds, while near surface temperature and relative humidity are similar to WRF. Results show that the sea breeze occurred around 20% of the two summer periods of 2006 and 2007. Both observed data analysis and the numerical modelling results confirmed the existence of two thermally induced systems in the Auckland region. Bay breezes are initiated in the morning hours (0800 – 1000 hours) from small bodies of water (Manukau, Waitemata, and Kaipara Harbour, and along the Hauraki Gulf coastline), followed by mature sea breezes from the main bodies of water (Tasman Sea and larger Hauraki Gulf area) in the late morning. The cessation of sea breezes started after 1600 hours. Frequency of sea breeze days was the highest under coast-parallel gradient winds (southeast and northwest), with speeds < 6 m s-1. The predicted depth of the sea breeze inflow ranged between 200 and 600 m, while the depth of the return flow was in the range of 200 – 500 m. Sensible heat flux is an important control in the development of sea breeze over the region. Coastal mountain ranges helped early onset of the sea breeze, but also inhibited inland propagation. Strong jet-like westerly winds along the coastline near the Manukau Harbour are due partly to the narrow opening at the Manukau Head, reduced friction over the harbour water, and divergence of wind due to coastline shape. Gradient winds significantly affect the evolution of the sea breeze and modify many of its dynamics, such as the sea breeze inflow layer, return flow, inland penetration, sea breeze head, etc. Under northerly gradient flow northeast sea breeze lasts longer while under southerly gradient flow cessation of the westerly sea breeze was delayed. Over both east and west coasts, WRF predicted anticlockwise rotation, especially under easterly gradient wind conditions. However, inland stations near Manukau Harbour show partial and complete clockwise rotation, which is primarily due to orographic features of the region. The diurnal rotation of the sea breeze system may contribute to recirculation of pollutants in the morning hours under coast-parallel gradient wind conditions. Pollutants that are emitted during morning peak traffic hours and advected towards Manukau Harbour by the remnants of the land breeze may be returned by bay breezes in the mid morning hours. Mixed layer height over land before arrival of the sea breeze also varied a lot and ranged between 600 to 1400 m. A convective internal boundary layer (CIBL) forms in the surface layer after arrival of the sea breeze. The CIBL under coast parallel gradient winds was relatively shallow (200 – 400 m), while under coasts-normal gradient winds (southwest and northeast), the predicted depth was in the range of 400 to 500 m. However, the inland extent of the CIBL was greater under coast-normal winds, especially under south-westerly gradient winds. The ground level concentration of air pollutants thus can be increased during sea breeze inflow over the region. Both bay breeze and mature sea breeze contribute towards development, extent and strength of the sea breeze convergence zones (SBCZs). Gradient winds and terrain play an important role in the position and strength of SBCZs. Under strong south-westerly gradient flow, a SBCZ is formed along the eastern coastline, while under north-easterly gradient winds a SBCZ is formed along the west coastline. During coast-parallel gradient winds the SBCZ is formed in the middle of landmass, and is then gradually displaced eastward or westward depending on the balance between large scale PGF and surface friction effect. In addition to SBCZs, terrain and coastline-induced convergences were also evident. Higher ground level concentrations of pollutants are expected under coast-normal gradient winds, when SBCZs are formed in the middle of the land mass and the wind speed of the sea breeze inflow and the sea breeze front is relatively low. This may increase pollution concentration, especially in the evening hours, to unacceptable levels. Results of this research suggest that given the size, synoptic meteorology and specific geography of the region, significant recirculation of pollutants is not likely to happen to contribute to next day’s pollution. The pollutant concentration may increase in the SBCZs, but their ability to recirculate the pollutants requires more extensive research. A closed sea breeze circulation cell is unlikely to form in this region due to topographical influences and a strong gradient wind effect. The pollutant plume is expected to be advected in the return flow over the peaks of higher terrain and via the top of the convergence zones, but its remixing in the onshore flow is subject to many factors such as gradient wind speed and direction, direction of the return flow and nature (size and state) of the pollutant. In appropriate conditions, pollution levels may reach to unhealthy levels under coast-parallel gradient wind condition.

This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series. Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere. Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration. Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.

[Truncated abstract] The expansion of human populations in coastal land margins has resulted in major modifcations to estuarine ecosystems. The use of numerical models as predictive tools for assessing remediation strategies is increasing. However, parameterisation of physical processes, developed mainly through field investigations, is necessary for these models to be reliable and effective management tools. The physical processes in micro–tidal diurnal tidal systems are relatively unknown and the current study examines field measurements obtained from the upper Swan River estuary (Western Australia), a diurnal, partially mixed system during the summer when the freshwater discharge is negligible. The aims of the study were to characterise, temporally and spatially, the dominant physical processes and associated sediment resuspension. Variability at three dominant time-scales were examined: 1) sub–tidal oscillations (∼5 to 10 days) resulting from local and remote forcing; 2) tidal (∼ 24 hours) due to astronomical forcing; and 3) intra-tidal (∼2 to 3 hours) resulting from the interaction between tidal constituents. Circulation in estuaries is widely accepted in the literature to be dominated, in varying proportions, by tidal range, freshwater discharge and gravitational circulation. In the upper Swan River estuary sub–tidal oscillations were responsible for the largest upstream displacement of the salt wedge in the absence of freshwater discharge. Moreover, these sub–tidal fluctuations in water level modified the ‘classic’ estuarine circulation. The dynamics of diurnal tides are largely controlled by the tropic month, which oscillates at a slightly different period to the lunar month, resulting in the spring–neap tidal cycle to be sometimes different from syzygy. The phase lag between the diurnal (O1 + K1) and semi-diurnal (M2 + S2) constituents, at the seasonal time scale cause the maximum tidal range to be near the solstice. Over a 24–hour tidal cycle this phase lag is manifested as an intra–tidal oscillation that occurs on the flood tide. Turbidity events that last ∼1 to 2 hours occur during the intra–tidal oscillation, but are not related to maximum shear stress predicted from the mean flow characteristics. The increases in turbidity during the intra–tidal oscillation is, however, correlated with the near–bed Reynolds fluxes. During the intra–tidal oscillation advection opposes the estuarine circulation in the near–bed region, promoting vertical shear that results in destratifcation of the water column. The turbulent mixing generated at the interface and in the near–bed region coincide with resuspension events. Similar turbidity data have often been disregarded and documented as being ‘spikes’ based on the premise that the mean flow was below a critical level to resuspend sediment. Resuspension events were not simply related to mean processes and may be controlled by turbulent instabilities generated when tidal currents reverse during an intra-tidal oscillation