logging in or signing up Weather & Climate - Rainfall arvindtirkey Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 934 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: February 22, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Slide 1: 1 W E L C O M E TO Prepared by: ARVIND TIRKEY Slide 2: 2 PRACTICAL WORK HOW TO MEASURE HUMIDITY & RAINFALL PREPARED BY – ARVIND TIRKEY 22O C 22O C Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITY : MEASURING RELATIVE HUMIDITY Amount of water vapour in the air is known as Humidity. The relative humidity is a measure of the amount of water vapor in the air (at a specific temperature) compared to the maximum amount of water vapor air could hold at that temperature, and is given as a percentage value. Relative humidity depends on the temperature of the air, as warm air can hold more moisture than cold air. A relative humidity of 100 percent indicates that the air is holding all the water it can at the current temperature, and any additional moisture at that point will result in condensation. A relative humidity of 50 percent means the air is holding half the amount of moisture that it could. 3 Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER : MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER 4 Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER : MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER The instrument for measuring relative humidity is known as a hygrometer. One common type of hygrometer is the WET AND DRY BULB HYGROMETER OR WET AND DRY BULB THERMOMETER. The dry bulb thermometer measures the normal temperature of the air. The wet bulb thermometer has a wet piece of muslin wrapped around its bulb. (muslin dipped in a dish of water and it absorbs the water from the dish). As the water evaporates from the muslin, its cooling effect on the bulb results in a lower temperature reading. How much water is evaporated from the muslin depends on the humidity of the air. The lower the humidity, the higher the amount of water that evaporates from the muslin. This leads to the stronger cooling effect on the bulb of the web-bulb thermometer, resulting in a lower temperature reading. The difference in the readings between the two thermometers is called the wet bulb depression. The values of the wet bulb depression and the dry bulb thermometer are used in conjunction with the relative humidity table to obtain the relative humidity (in terms of percentage). 5 Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITYEXAMPLE : MEASURING RELATIVE HUMIDITYEXAMPLE When air is not saturated, the two thermometers show different readings. But when the air is saturated, no evaporation occurs around the muslin and hence, there is no cooling effect. Both the wet and dry bulb thermometers show same reading. Therefore, the value of Wet Bulb Depression is 0o Celsius, indicating that the relative humidity is 100 per cent. For instance, if the dry-bulb thermometer measures 22O C and the wet-bulb thermometer measures 21O C, the wet – bulb depression is then 1O C. When the wet bulb depression is 1O C and the dry bulb thermometer is 22O C, the relative humidity is 90%. A relative humidity of 90% indicates that there is a lot of moisture in the air at that temperature. 6 Prepared by: ARVIND TIRKEY RELATIVE HUMIDITY TABLE : RELATIVE HUMIDITY TABLE 7 Prepared by: ARVIND TIRKEY RAINFALL : 8 RAINFALL The pouring down of water droplets on the ground from the clouds. When could rises up or is blown to a cooler region the small droplets of water become colder and they join together to form bigger drops. These bigger droplets cannot float in the air due to their weight. They fall through the air on the ground as rain. Prepared by: ARVIND TIRKEY RAIN GAUGE : 9 RAIN GAUGE Parts of a Rain Gauge. What are the different parts of a simple rain gauge? Why is the hole in the metal funnel very small? Prepared by: ARVIND TIRKEY HOW TO MEASURE RAIN ? : 10 HOW TO MEASURE RAIN ? RAINFALL IS MEASURED BY RAIN GAUGE. A SIMPLE RAIN GAUGE CONSISTS OF AN OUTER CASING, A COPPER CYLINDER, A METAL FUNNEL WHICH LEADS INTO A GLASS BOTTLE AND A MEASURING CYLINDER. THE BOTTLE IS FITTED WITH A FUNNEL AT ITS MOUTH. THE AMOUNT OF RAIN WATER COLLECTED IN THE BOTTLE IS MEASURED IN A GRADUATED GLASS. AREA OF THE GLASS MOUTH BEARS A FIXED RATIO TO THE AREA OF THE MOUTH OF THE FUNNEL. MOST OF THE TIME THIS RATIO IS 1:10 ONE CUBIC cm OF RAIN IN THIS GRADUATED GLASS DENOTES 1MM RAINFALL. Prepared by: ARVIND TIRKEY RAINGAUGE : 11 RAINGAUGE Prepared by: ARVIND TIRKEY RAINGAUGE : 12 RAINGAUGE Prepared by: ARVIND TIRKEY RAINGAUGE : 13 RAINGAUGE Prepared by: ARVIND TIRKEY PRECAUTIONS FOR MEASURING RAINFALL : 14 PRECAUTIONS FOR MEASURING RAINFALL RAIN GAUGE SHOULD BE KEPT IN OPEN. IT SHOULD BE KEPT AWAY FROM THE TREE AND BUILDINGS TO AVOID ALL HINDERENCES. IT SHOULD BE KEPT ON A LEVELLED PLACE ATLEAST 3 TO 300 CM ABOVE THE GROUND LEVEL. NO SEEPAGE OR EVAPORATION OF THE RAIN WATER SHOULD TAKE PLACE. NO DROP OF WATER SHOULD FALL ON THE GROUND WHILE MEASURING IT IN THE MEASURING GLASS. Prepared by: ARVIND TIRKEY CALCULATING RAINFAL : CALCULATING RAINFAL 15 Prepared by: ARVIND TIRKEY CALCULATING RAINFAL : CALCULATING RAINFAL TOTAL MONTHLY RAINFALL This is obtained by adding the total daily rainfall for the month. The total monthly rainfall = sum of all the total daily rainfall for the month = ? 29.5 mm 16 Prepared by: ARVIND TIRKEY CALCULATING RAINFALL – Total Annual Rainfall : CALCULATING RAINFALL – Total Annual Rainfall TOTAL ANNUAL RAINFAL This is obtained by adding the total monthly rainfall for twelve months. Total annual rainfall = sum of all the total monthly rainfall for twelve months = ? 2332.6 mm Draw a rainfall bar graph using the table given above. The horizontal scale represents months and the vertical scale the total rainfall per month. 17 Prepared by: ARVIND TIRKEY Slide 18: Rainfall (mm) months 18 Prepared by: ARVIND TIRKEY ANY QUESTIONS : 19 ANY QUESTIONS ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Prepared by: ARVIND TIRKEY BIBLIOGRAPHY : BIBLIOGRAPHY Chun, Tham Yoke. Understanding Geography 3. 1st Reprint. Singapore: Addison Wesley Longman Singapore Pte Ltd, 1999. 69-74. Print. Bunnet, R B. Interactive Geography 3. 2nd Reprint. Singapore: SNP Panpac Pte Ltd, 2001. Page 28. Print. Images (Google Image Search). 20 Prepared by: ARVIND TIRKEY Read a Climograph – Climograph for Singapore : Read a Climograph – Climograph for Singapore 21 Prepared by: ARVIND TIRKEY Steps: Read the title. In figure the title shows the climograph for Singapore. Study the scale shown on the horizontal and vertical axes. The temperature is represented as a line graph and precipitation as a bar graph. Analyse the data. Line graph indicates mean monthly temperatures for a year. Obtain the lowest and highest monthly temperatures and the months with these temperature. Calculate mean annual temperature, annual temperature range, total annual precipitation and describe the distribution of precipitation – e.g. distinct wet, dry or evenly distributed precipitation and months with max. & min. precipitation. Read a Climograph – Interpret the Graph/data : Read a Climograph – Interpret the Graph/data 22 Prepared by: ARVIND TIRKEY Steps: 4. Interpret the data. Based on the patterns observed, make a generalisations on the temperature and precipitation of a place in the following way: Distribution of temperature throughout the year – uniform or seasonal. Mean annual temperature – low or high. Annual temperature range – small or large. Annual precipitation distribution – whether seasonal or distributed throughout the year. The figure below shows some terms which can be used in describing these patterns. Read a Climograph – Interpret the Graph/data : Read a Climograph – Interpret the Graph/data 23 Prepared by: ARVIND TIRKEY Responses: Instructions. Instructions. The lowest monthly temperature for Singapore is 26O C and the highest is 28O C. The months with the highest and lowest temperatures are May and December respectively. The mean annual temperature is 26.9O C and the annual temperature range is 2O C. The total annual precipitation for Singapore is about 2275mm which is distributed throughout the year. The months with the maximum precipitation are November to January and the months with minimum precipitation are February and May to July. Singapore has a high uniform mean annual temperature of about 27O C. The annual temperature range of about 2O C is small. As all the months experiences rainfall, the total annual precipitation is evenly distributed throughout the year. You do not have the permission to view this presentation. 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Weather & Climate - Rainfall arvindtirkey Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 934 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: February 22, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Slide 1: 1 W E L C O M E TO Prepared by: ARVIND TIRKEY Slide 2: 2 PRACTICAL WORK HOW TO MEASURE HUMIDITY & RAINFALL PREPARED BY – ARVIND TIRKEY 22O C 22O C Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITY : MEASURING RELATIVE HUMIDITY Amount of water vapour in the air is known as Humidity. The relative humidity is a measure of the amount of water vapor in the air (at a specific temperature) compared to the maximum amount of water vapor air could hold at that temperature, and is given as a percentage value. Relative humidity depends on the temperature of the air, as warm air can hold more moisture than cold air. A relative humidity of 100 percent indicates that the air is holding all the water it can at the current temperature, and any additional moisture at that point will result in condensation. A relative humidity of 50 percent means the air is holding half the amount of moisture that it could. 3 Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER : MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER 4 Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER : MEASURING RELATIVE HUMIDITYHYGROMETER – WET & DRY BULB THERMOMETER The instrument for measuring relative humidity is known as a hygrometer. One common type of hygrometer is the WET AND DRY BULB HYGROMETER OR WET AND DRY BULB THERMOMETER. The dry bulb thermometer measures the normal temperature of the air. The wet bulb thermometer has a wet piece of muslin wrapped around its bulb. (muslin dipped in a dish of water and it absorbs the water from the dish). As the water evaporates from the muslin, its cooling effect on the bulb results in a lower temperature reading. How much water is evaporated from the muslin depends on the humidity of the air. The lower the humidity, the higher the amount of water that evaporates from the muslin. This leads to the stronger cooling effect on the bulb of the web-bulb thermometer, resulting in a lower temperature reading. The difference in the readings between the two thermometers is called the wet bulb depression. The values of the wet bulb depression and the dry bulb thermometer are used in conjunction with the relative humidity table to obtain the relative humidity (in terms of percentage). 5 Prepared by: ARVIND TIRKEY MEASURING RELATIVE HUMIDITYEXAMPLE : MEASURING RELATIVE HUMIDITYEXAMPLE When air is not saturated, the two thermometers show different readings. But when the air is saturated, no evaporation occurs around the muslin and hence, there is no cooling effect. Both the wet and dry bulb thermometers show same reading. Therefore, the value of Wet Bulb Depression is 0o Celsius, indicating that the relative humidity is 100 per cent. For instance, if the dry-bulb thermometer measures 22O C and the wet-bulb thermometer measures 21O C, the wet – bulb depression is then 1O C. When the wet bulb depression is 1O C and the dry bulb thermometer is 22O C, the relative humidity is 90%. A relative humidity of 90% indicates that there is a lot of moisture in the air at that temperature. 6 Prepared by: ARVIND TIRKEY RELATIVE HUMIDITY TABLE : RELATIVE HUMIDITY TABLE 7 Prepared by: ARVIND TIRKEY RAINFALL : 8 RAINFALL The pouring down of water droplets on the ground from the clouds. When could rises up or is blown to a cooler region the small droplets of water become colder and they join together to form bigger drops. These bigger droplets cannot float in the air due to their weight. They fall through the air on the ground as rain. Prepared by: ARVIND TIRKEY RAIN GAUGE : 9 RAIN GAUGE Parts of a Rain Gauge. What are the different parts of a simple rain gauge? Why is the hole in the metal funnel very small? Prepared by: ARVIND TIRKEY HOW TO MEASURE RAIN ? : 10 HOW TO MEASURE RAIN ? RAINFALL IS MEASURED BY RAIN GAUGE. A SIMPLE RAIN GAUGE CONSISTS OF AN OUTER CASING, A COPPER CYLINDER, A METAL FUNNEL WHICH LEADS INTO A GLASS BOTTLE AND A MEASURING CYLINDER. THE BOTTLE IS FITTED WITH A FUNNEL AT ITS MOUTH. THE AMOUNT OF RAIN WATER COLLECTED IN THE BOTTLE IS MEASURED IN A GRADUATED GLASS. AREA OF THE GLASS MOUTH BEARS A FIXED RATIO TO THE AREA OF THE MOUTH OF THE FUNNEL. MOST OF THE TIME THIS RATIO IS 1:10 ONE CUBIC cm OF RAIN IN THIS GRADUATED GLASS DENOTES 1MM RAINFALL. Prepared by: ARVIND TIRKEY RAINGAUGE : 11 RAINGAUGE Prepared by: ARVIND TIRKEY RAINGAUGE : 12 RAINGAUGE Prepared by: ARVIND TIRKEY RAINGAUGE : 13 RAINGAUGE Prepared by: ARVIND TIRKEY PRECAUTIONS FOR MEASURING RAINFALL : 14 PRECAUTIONS FOR MEASURING RAINFALL RAIN GAUGE SHOULD BE KEPT IN OPEN. IT SHOULD BE KEPT AWAY FROM THE TREE AND BUILDINGS TO AVOID ALL HINDERENCES. IT SHOULD BE KEPT ON A LEVELLED PLACE ATLEAST 3 TO 300 CM ABOVE THE GROUND LEVEL. NO SEEPAGE OR EVAPORATION OF THE RAIN WATER SHOULD TAKE PLACE. NO DROP OF WATER SHOULD FALL ON THE GROUND WHILE MEASURING IT IN THE MEASURING GLASS. Prepared by: ARVIND TIRKEY CALCULATING RAINFAL : CALCULATING RAINFAL 15 Prepared by: ARVIND TIRKEY CALCULATING RAINFAL : CALCULATING RAINFAL TOTAL MONTHLY RAINFALL This is obtained by adding the total daily rainfall for the month. The total monthly rainfall = sum of all the total daily rainfall for the month = ? 29.5 mm 16 Prepared by: ARVIND TIRKEY CALCULATING RAINFALL – Total Annual Rainfall : CALCULATING RAINFALL – Total Annual Rainfall TOTAL ANNUAL RAINFAL This is obtained by adding the total monthly rainfall for twelve months. Total annual rainfall = sum of all the total monthly rainfall for twelve months = ? 2332.6 mm Draw a rainfall bar graph using the table given above. The horizontal scale represents months and the vertical scale the total rainfall per month. 17 Prepared by: ARVIND TIRKEY Slide 18: Rainfall (mm) months 18 Prepared by: ARVIND TIRKEY ANY QUESTIONS : 19 ANY QUESTIONS ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Prepared by: ARVIND TIRKEY BIBLIOGRAPHY : BIBLIOGRAPHY Chun, Tham Yoke. Understanding Geography 3. 1st Reprint. Singapore: Addison Wesley Longman Singapore Pte Ltd, 1999. 69-74. Print. Bunnet, R B. Interactive Geography 3. 2nd Reprint. Singapore: SNP Panpac Pte Ltd, 2001. Page 28. Print. Images (Google Image Search). 20 Prepared by: ARVIND TIRKEY Read a Climograph – Climograph for Singapore : Read a Climograph – Climograph for Singapore 21 Prepared by: ARVIND TIRKEY Steps: Read the title. In figure the title shows the climograph for Singapore. Study the scale shown on the horizontal and vertical axes. The temperature is represented as a line graph and precipitation as a bar graph. Analyse the data. Line graph indicates mean monthly temperatures for a year. Obtain the lowest and highest monthly temperatures and the months with these temperature. Calculate mean annual temperature, annual temperature range, total annual precipitation and describe the distribution of precipitation – e.g. distinct wet, dry or evenly distributed precipitation and months with max. & min. precipitation. Read a Climograph – Interpret the Graph/data : Read a Climograph – Interpret the Graph/data 22 Prepared by: ARVIND TIRKEY Steps: 4. Interpret the data. Based on the patterns observed, make a generalisations on the temperature and precipitation of a place in the following way: Distribution of temperature throughout the year – uniform or seasonal. Mean annual temperature – low or high. Annual temperature range – small or large. Annual precipitation distribution – whether seasonal or distributed throughout the year. The figure below shows some terms which can be used in describing these patterns. Read a Climograph – Interpret the Graph/data : Read a Climograph – Interpret the Graph/data 23 Prepared by: ARVIND TIRKEY Responses: Instructions. Instructions. The lowest monthly temperature for Singapore is 26O C and the highest is 28O C. The months with the highest and lowest temperatures are May and December respectively. The mean annual temperature is 26.9O C and the annual temperature range is 2O C. The total annual precipitation for Singapore is about 2275mm which is distributed throughout the year. The months with the maximum precipitation are November to January and the months with minimum precipitation are February and May to July. Singapore has a high uniform mean annual temperature of about 27O C. The annual temperature range of about 2O C is small. As all the months experiences rainfall, the total annual precipitation is evenly distributed throughout the year.