یادداشتهای مربوط به کتابنامه ، واژه نامه و نمایه های داخل اثر
متن يادداشت
واژه نامه به صورت زیرنویس
متن يادداشت
کتابنامه ص :۱۴۶-۱۴۹
یادداشتهای مربوط به پایان نامه ها
جزئيات پايان نامه و نوع درجه آن
کارشناسی ارشد
نظم درجات
جغرافیای طبیعی
زمان اعطا مدرک
۱۳۸۲/۰۶/۳۰
کسي که مدرک را اعطا کرده
تبریز : دانشگاه تبریز ، علوم انسانی و اجتماعی ، اقلیم شناسی در برنامه محیطی
یادداشتهای مربوط به خلاصه یا چکیده
متن يادداشت
پایاننامه حاضر با هدف مطالعه پدیده یخبندان، با فرض بر اینکه این پدیده دارای نوسان زمانی و مکانی بوده و نیز از توزیع نرمال پیروی میکند، آغاز شد .یخبندان که در اثر افت درجه حرارت حداقل روزانه هوا به صفرو زیرصفر درجه سانتیگراد بوجود میآید، وقوع نابهنگام آن در آغاز فصل رشد(فصل بهار)باعث نابودی بافتهای نورس گیاهان، جوانه و شکوفه درختان میوه شده و در مراحل پایانی فصل رشد) فصل پاییز (به بسیاری از محصولات کشاورزی برداشت نشده خسارات سنگینی وارد میسازد.برای مطالعه نوسان یخبندان و کاربرد نتایج آن در بازدهی محصولات کشاورزی، محدوده حوضه آبریز جنوبی رود ارس که با مساحت ۳۹۴۷۸ کیلومتر مربع در شمال ناحیه شمالغرب ایران قرار دارد، بعنوان مکان تحقیق انتخاب شد .سپس جهت انجام مراحل بعدی تحقیق، تعداد زیادی از منابع داخلی و خارجی که درباره وقوع پدیده یخبندان، تحقیقاتی در آنها صورت گرفته بود مورد بررسی و ارزیابی قرار گرفت .در نهایت مشخص شد که در اغلب منابع مذکور بخصوص منابع خارجی، با استفاده از روشهای پیشرفته آماری و درجه حرارت حداقل روزانه، تاریخهای وقوع آخرین یخبندان بهاره، اولین یخبندان پاییزه و طول فصل رشد، مورد تجزیه و تحلیل قرار گرفته است.
متن يادداشت
The work of present thesis began with the purpose of studying frost phenomenon, assuming that, it has temporal and spatial variations and it characterizes the normal distribution. The frost which is caused by at least a daily temperature of zero centigrade and lower than it, while occurs prematurely, can cause destruction of newly grown plant tissues, buds and blossoms of fruit trees in the beginning of growth season (the spring), and in the last stages of growing season (the fall) can damage almost of still not - harvested crops.In order to studying the frost variations and their application in agricultural crop production, we choose the south basin of the Aras River (having an area of 39478 square kilometers and situated in north-west of Iran) as research subject.Then domestic and international literature were reviwed for similar studies of frost phenomenon. We found out that these articles used progressive statistical methodologies and analyzed records of daily minimum temperature, the dates of the last spring frost occurances, the first autumnal frosts, and some data about duration of growth season.So, we analyzed following parameters in our study, according to the collected data from seven meteorological station in the south basin of the Aras; daily temperature, and statistical parameters, such as normal distribution, Skewness coefficient, correlation coefficient, linear regression, trend line, climate departure index, student t distribution, long-standing average and variations of frost occurance dates, duration of growth season and the minimum daily temperature, were analyzed.Some of the important results deducted from analyzing frost occurance dates and the duration of growth season recorded in studied stations are as follow:The julian day-numbers of frost occurance dates and duration of growth season, obey the normal distribution, and the inclination ration of "frost occurance dates" to "premature autumnal and serotinal spring frosts" in the recording stations, as a whole, was not identical.Correlation coefficient between the dates of the first autumnal and the last spring frost occurance dates, and the time (of the year) in the stations was a weak correlation, except in Ardebil station. The dates of frost occurance and the duration of growth season for any unit of increase of time unit had a gradual variation and the direction of these changes were usually different in the mentioned stations. Spring frosts and autumnal frosts occured four times and twice a year, respectively, and had deviations from their own averages. The dates of spring frosts tended to occur in the middle of spring and the autumnal ones tended to occur in the early part of the winter during 1985-1999, so, the time of beginning and the finishing the growth season in the South basin of Aras has bean displaced and according to the time changing of beginning and finishing of growth season and the statistical result of the sixth chapter of this thesis showed that, the early-planted and late-harvested crops and early-blooming fruit trees of South basin of Aras River are more at the risk of freezing and frost phenomenon.Considering the acquried results, the latest occuring spring frosts, in almost recording stations, have been registered in a roughly a similar and close dates and it was universal, but the most premature autumnal frosts have been recorded significantly different in any station. The beginning time of autumnal frosts in South basin of Aras River follow the local and natural features, and the spring frost occurances, specially late-occured spring frosts, abey the external factors such as intruding cold air mass etc.
موضوع (اسم عام یاعبارت اسمی عام)
موضوع مستند نشده
Frost
موضوع مستند نشده
minimum daily temperature
موضوع مستند نشده
south basin of Aras River
نام شخص به منزله سر شناسه - (مسئولیت معنوی درجه اول )