Modul Praktikum Agroklimatologi Universitas Sriwijaya 2016 [PDF]

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MODUL PRAKTIKUM AGROKLIMATOLOGI



Oleh : Tim Asisten



Nama : NIM : Kelas :



JURUSAN BUDIDAYA PERTANIAN FAKULTAS PERTANIAN UNIVERSITAS SRIWIJAYA INDRALAYA 2016 DAFTAR MATERI PRAKTIKUM AGROKLIMATOLOGI SEMESTER GANJIL TAHUN 2016



No. 1. 2. 3. 4. 5. 6.



Materi



Hlm.



Pengukuran Curah Hujan...................................................................... Pengukuran Suhu dan Kelembaban...................................................... Pengukuran Lama Penyinaran Matahari............................................. Pengukuran Kecepatan Angin................................................................ Pengenalan Alat Solarimeter (Lightmeter)........................................... Pengenalan Alat Open Pan Evaporimeter & Lysimeter...…………….



DAFTAR NAMA ASISTEN



2



4 8 12 16 20 24



No



Nama



NIM



Ttd



1.



Sampurna Wijaya



05071181320027



2.



Bobot Sudoyo



05071181320062



3.



Slamet Triyadi



05071281320009



4.



Diany Puspa Nirwana



05071281419185



5.



M. Deni



05071281419188



6.



Putri Wulandari



05071181419176



7.



Aria Thamara



05071181419048



8.



Kharis Edi Wardana



05071281419100



9.



Habibulloh



05071281419088



10.



Muhardianto Cahya



05071281419097



11.



Sahrul Lindra



05071181419181



12.



Wahyu Hidayat



05071281419067



13. 14.



Koordinator Praktikum,



Koordinator Asisten,



Dr. Ir. Zaidan Panji Negara. M.Sc NIP. 195906211986021001



Sampurna Wijaya NIM. 05071181320027



LAPORAN PRAKTIKUM AGROKLIMATOLOGI 3



PENGUKURAN CURAH HUJAN Hari/Tanggal :`



AsistenKelas :



Nama



:



1.



NIM



:



2.



Kelompok



:



3. 4. 5.



A. Dasar Teori Hujan memainkan peran penting dalam siklus hidrologi. Hujan merupakan rangkaian dari terjadinya konveksi – evaporasi/evapotranspirasi – kondensasi– presipitasi. Konveksi adalah proses pemindahan panas oleh gerak massa suatu fluida dari suatu daerah ke daerah lainnya. Evaporasi adalahproses penguapan air yang terdiri dari air laut, air sungai, air tanah, air limbah, dan sebagainya akibat adanya bantuan dari panas sinar matahari. Evapotranspirasi adalah adalahproses penguapan air yang berasal dari vegetasi atau tumbuhan akibat adanya bantuan dari panas sinar matahari. Kondensasi adalah uap-uap air mengalami proses pemadatan di udara sehingga terbentuklah awan. Akibat terbawa angin yang bergerak, awan-awan tersebut saling bertemu dan membesar dan kemudian menuju ke atmosfir bumi yang suhunya lebih rendah atau dingin dan akhirnya membentuk butiran es dan air. Terjadinya proses presipitasi karena terlalu berat dan tidak mampu lagi ditopang angin akhirnya butiran-butiran air atau es tersebut jatuh ke permukaan bumi. Jika awan berada pada posisi yang rendah, mengakibatkan suhu semakin naik maka es/salju akan mencair, namun jika suhunya sangat rendah, maka akan turun menjadi salju. Jumlah air hujan diukur menggunakan pengukur hujanatau ombrometer. Satuan curah hujan menurut SI adalah milimeter, yang merupakan penyingkatan dari liter per meter persegi. B. Tujuan Agar mahasiswa mengetahui dan mampu melakukan pengukuran curah hujan dengan alat penangkar hujan buatan atau dengan alat automatis tipe observatorium.



C. Alat dan Bahan 4



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LAPORAN PRAKTIKUM AGROKLIMATOLOGI PENGUKURAN SUHU DAN KELEMBABAN



7



Hari/Tanggal:`



AsistenKelas :



Nama



:



1.



NIM



:



2.



Kelompok



:



3. 4. 5.



A. Dasar Teori Suhu udara adalah keadaan panas atau dinginnya udara.Biasanya pengukur dinyatakan dalam skala Celcius (C), Reamur (R), dan Fahrenheit (F). Suhu udara tertinggi dimuka bumi adalah didaerah tropis (sekitar ekuator) dan makin ke kutub semakin dingin. Kita sudah mengetahui bahwa tiap kenaikan bertambah 100 meter maka suhu akan berkurang (turun) rata-rata 0,6 ˚C. Penurunan suhu semacam ini disebut gradient temperatur vertikal atau lapse rate. Pada udara kering, lapse rate adalah 1 ˚C (Benyamin, 1997). Alat pengukur suhu disebut thermometer. Thermometer yang digunakan dalam praktikum ini ialah thermometer maksimum dan thermometer minimum, bola basah dan bola kering. Secara ilmiah, kelembaban merupakan jumlah kandungan uap air yang terkandung dalam massa udara pada suatu saat (waktu) dan wilayah (tempat) tertentu. Adapun alat yang digunakan untuk mengukur kelembaban adalah tigrometer. Suhu dan kelembaban udara sangat erat hubungannya, karena jika kelembaban udara berubah, maka suhu juga akan berubah. Di musim penghujan suhu udara rendah, kelembaban tinggi, memungkinkan tumbuhnya jamur pada kertas, atau kertas menjadi bergelombang karena naik turunnya suhu udara. B. Tujuan 1. Agar mahasiswa dapat menjelaskan pengertian suhu dan kelembaban. 2. Agar mahasiswa mengerti bagaimana cara mengukur suhu di udara.



C. Alat dan Bahan ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................



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LAPORAN PRAKTIKUM AGROKLIMATOLOGI PENGUKURAN LAMA PENYINARAN MATAHARI Hari/Tanggal:`



AsistenKelas :



Nama



:



1.



NIM



:



2.



Kelompok



:



3. 11



4. 5. A. Dasar Teori Matahari adalah sumber panas bagi bumi. Faktor-faktor yang mempengaruhi tinggi rendahnya suhu udara dari matahari di suatu daerah adalah, (1) Lamanya penyinaran matahari, (2) Sudut datang sinar matahari. Faktor lamanya penyinaran matahari dapat diukur yaitu dengan menggunakan Aktinograf dan Solarimeter. Dalam menggunakan Aktinograf dapat menggunakan tipe Camble Stokes. Selain Camble Stokes, ada pula dikenal tipe Foster, tipe Marvin, dan tipe Jordan. Prinsip alat Camble Stokes adalah pembakaran pias. Panjang pias yang terbakar dinyatakan dalam jam. Alat ini mengukur lama penyinaran surya. Hanya pada keadaan matahari terang saja pias terbakar, sehingga yang terukur adalah lama penyinaran surya terang. Ada 3 tipe pias yang digunakan : 1. Pias waktu matahari di ekuator 2. Pias waktu matahari di utara 3. Pias waktu matahari di selatan B. Tujuan 3. Agar mahasiswa dapat menjelaskan pengertian lama penyinaran matahari. 4. Agar mahasiswa mengerti bagaimana cara mengukur persen lama penyinaran matahari ke bumi.



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LAPORAN PRAKTIKUM AGROKLIMATOLOGI PENGUKURAN KECEPATAN ANGIN Hari/Tanggal :`



AsistenKelas :



Nama



:



1.



NIM



:



2.



Kelompok



:



3. 4. 5.



A. Dasar Teori Angin merupakan gerakan udara dari daerah bertekanan tinggi menuju daerah pergerakan rendah yang arahnya horizontal atau hampir horizontal dengan permukaan bumi. 15



Sedangkan pergerakan udara arah vertikal dinamai aliran udara. Udara merupakan campuran mekanis gas yang berada pada atmosfer. Kecepatan angin adalah jarak yang ditempuh oleh angin dalam per satuan waktu. Kecepatan angin dinyatakan dalam knot/ jam,km/jam dan m/dtk. Kecepatan angin dalam klimatologi adalah kecepatan angin horizontal pada ketingian dua meter dari permukaan tanah yang ditanami dengan rumput. Kecepatan angin pada dasarnya ditentukan oleh perbedaan tekanan udara antara tempat asal dan tujuan angin (sebagai faktor pendorong ) dan resistensi medan yang dilaluinya. Alat-alat yang paling baik untuk mengukur angin (permukaan) adalah Wind Vane dan Anemometer. Alat-alat pengukur kecepatan angin di bagi dalam 3 bagian : 1. Anemometer Cup dan Vane, alat ini mengukur banyaknya udara yang melalui alat per satuan waktu. 2. Pressure Tube Anemometer, alat ini bekerja disebabkan oleh tekanan dari aliran udara yang melalui pipa-pipanya. 3. Pressure Plate Anemometer, lembaran logam tertentu, ditempatkan tegak lupus angin. Lembaran logam ini akan berputar pada salah satu sisinya sebagai sumbu. Besar penyimpangan (sudut) menjadi kecepatan angin. C. Tujuan Agar mahasiswa dapat menjelaskan pengertian angin, udara, dan mampu mengetahui bagaimana mengukur kecepatan angin dengan anemometer. C. Alat dan Bahan ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... D. Pembahasan 16



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LAPORAN PRAKTIKUM AGROKLIMATOLOGI PENGENALAN ALAT SOLARIMETER (LIGHT/LUX-METER) Hari/Tanggal :`



AsistenKelas :



Nama



:



1.



NIM



:



2.



Kelompok



:



3. 4. 5.



A. Dasar Teori Lux meter merupakan sebuah alat yang digunakan untuk mengukur intensitas cahaya di sebuah tempat atau ruangan. Alat ini menggunakan satuan lux dalam pengukurannya. Pada lux meter terdapat sebuah sensor cahaya yang bertugas untuk mengubah cahaya menjadi angka-angka yang kemudian akan dibaca oleh lux meter. 19



Pada praktikum ini akan menggunakan light/lux-meter dengan mempunyai range intensitas cahaya 1-400,000 lux. D. Tujuan Agar mahasiswa dapat menjelaskan pengertian solarimeter dan mampu mengukur intensitas cahaya matahari dengan light/lux-meter. C. Alat dan Bahan ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................



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LAPORAN PRAKTIKUM AGROKLIMATOLOGI PENGENALAN ALAT OPEN PAN EVAPORIMETER & LYSIMETER Hari/Tanggal :`



AsistenKelas :



Nama



:



1.



NIM



:



2.



Kelompok



:



3. 4. 5.



A. Dasar Teori Penguapan atau evaporasi adalah proses perubahan molekul di dalam keadaan cair (contohnya air) dengan spontan menjadi gas (contohnya uap air). Proses ini adalah kebalikan dari kondensasi. Umumnya penguapan dapat dilihat dari lenyapnya cairan secara berangsurangsur ketika terpapar pada gas dengan volume signifikan.Rata-rata molekul tidak memiliki energi yang cukup untuk lepas dari cairan. Bila tidak cairan akan berubah menjadi uap dengan cepat. Ketika molekul-molekul saling bertumbukan mereka saling bertukar energi 23



dalam berbagai derajat, tergantung bagaimana mereka bertumbukan. Terkadang transfer energi ini begitu berat sebelah, sehingga salah satu molekul mendapatkan energi yang cukup buat menembus titik didih cairan. Bila ini terjadi di dekat permukaan cairan molekul tersebut dapat terbang ke dalam gas dan "menguap". Ada cairan yang kelihatannya tidak menguap pada suhu tertentu di dalam gas tertentu (contohnya minyak makan pada suhu kamar). Cairan seperti ini memiliki molekul-molekul yang cenderung tidak menghantar energi satu sama lain dalam pola yang cukup buat memberi satu molekul "kecepatan lepas" - energi panas - yang diperlukan untuk berubah menjadi uap. Namun cairan seperti ini sebenarnya menguap, hanya saja prosesnya jauh lebih lambat dan karena itu lebih tak terlihat. Penguapan adalah bagian esensial dari siklus air. Energi surya menggerakkan penguapan air dari samudera, danau, embun dan sumber air lainnya. Dalam hidrologi penguapan dan transpirasi (yang melibatkan penguapan di dalam stomata tumbuhan) secara kolektif diistilahkan sebagai evapotranspirasi. Ada beberpaalat yang digunakan untuk mengukur penguapan, diantaranya adalah Open Pan Evaporimeter dan Lysimeter.



B. Tujuan Agar mahasiswa dapat mengetahui salah satu cara yang dapat digunakan untuk menghitung besarnya kehilangan air yang terjadi akibat penguapan (Evapotranspirasi). C. Alat dan Bahan ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................



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