How to fish in the weather with large temperature difference

We know that the temperature difference has a great influence on fishing. The author went to the drugstore again and again and bought several thermometers. Salespeople may be a little surprised. When measuring the water temperature at the water's edge, sometimes I forgot to collect it, sometimes I accidentally fell into the water, and sometimes I stepped on it. I'm a little old and confused. I really want to find some objective laws by measuring various temperatures, but I haven't found anything meaningful so far. But through sporadic accumulation, I also noticed some immature laws and made them public. I also talked about the influence of temperature difference on fishing.

First, the influence of temperature difference at night on fishing

During the day, from dusk to dawn the next day, the temperature gradually drops. The extent of the decline is large and small. The temperature difference after dusk, around 7 pm and around 7 am the next day is called night temperature difference (5 am may be more accurate, but it is inconvenient to get up early). The indoor temperature difference is small, so I use the temperature difference outside the balcony window.

I noticed that the temperature difference at night has a lot to do with fishing. In late autumn, winter and early spring, when the temperature difference at night is greater than 5 degrees Celsius, it is difficult to fish, and it is likely to play whiteboard (when in the air force). When you go to ponds and rivers, you often see the muddy water on the shore become clear, even clear to the bottom. This is because the temperature drops a lot at night, which is particularly cold, and the fish hide in the deep water, so the water on the shore is particularly clear. Two days later, the fish still felt cold and was too lazy to talk. After fishing all day, I often can't see the float moving. On the contrary, the temperature difference at night is less than 2 degrees Celsius, and the temperature drops very little at night, so the fish will not feel particularly cold. They still swim around at night and feed normally for the next two days. Fishing in this weather will pay off.

On February 20th, outdoor temperature was 4 degrees at night, 2 1 outdoor temperature was 3 degrees in the morning, and the temperature difference at night was 1 degree. He Diaoyou caught 6 Jin in a small pond. February 24 is 2 am, 7 pm the day before, and the temperature difference is 5 pm. I went to the pond with another fisherman, and the effect was very poor. Two people split half a catty. It was rainy and cool on March 26th, and the temperature difference at night was 4 degrees (16— 14). We went fishing in a pond in Dongxing. Jiang Diaoyou caught four crucian carp (half a catty), and I also caught four for the other one. The next night, the temperature difference 1 degree, (13- 12), ginger went to the pond again, and it is said that he gained 5 kg.

Although the temperature difference at night is not the only decisive factor, it is really important. It has been verified many times that when the temperature difference is greater than 5 degrees, it is not suitable for fishing, and it is difficult to catch a few fish without playing the whiteboard. When the temperature difference is less than 2 degrees at night, it is not necessarily a good harvest, because there are many influencing factors. But you can go fishing and get some more or less.

It can be inferred that the temperature difference at night in summer will also have an impact on fishing. But it should be that the greater the temperature difference at night, the better fishing in the next two days. In summer, the temperature drops a lot at night, so fish feel cool and active at night, which is suitable for fishing the next morning. It is common to catch fish in early summer.

The effect of fishing in early summer depends largely on the temperature difference at night. This is just speculation and I believe it can be verified.

2. The influence of temperature difference between day and night on fishing

The highest temperature is about 2-3 pm, and the lowest temperature is about 5-6 pm before dawn. The greater the difference between the highest and lowest temperatures within 24 hours, the more difficult it is to fish. The main reason for the large temperature difference is sunny and the sun is big. The bright red sun makes the surface water temperature rise rapidly, causing the temperature difference between the surface water and the bottom water to widen, which affects the foraging activities of fish.

The daily maximum and minimum temperatures provided by the weather forecast can be referred to. If there is little difference between the two, it is more suitable for fishing. On the other hand, if the temperature difference between day and night is large, the harvest of fishing may not be much.

The fishing situation in March 10 is a good example. Weather forecast for the first night: sunny to cloudy, 7-20 degrees Celsius (altitude difference 13 degrees). The temperature difference at night is 2 degrees (13— 1 1). Judging from the temperature difference at night, March 10 seems not bad, but it feels ok to go fishing in Dongjiahe in the morning. After noon, it is extremely difficult to fish, and almost no fish is served. The temperature measured at 8 o'clock is 9 degrees. Because the sun is big, the temperature measured at 3 pm is 25 degrees, rising as high as 17 degrees. The sun just rises in the morning, which has little effect on the temperature difference, making it easier to fish, while the temperature difference increases a lot in the afternoon, making it difficult to fish.

It is easy to fish on a cloudy day without cold wind in winter or on a cloudy day with flowers and sunshine (a little sunshine) because the temperature difference between day and night is small. On the contrary, the sun is shining, making people undress, and the temperature difference between day and night is large, making it difficult for fish to take the bait.

The temperature difference at night is large, and the temperature difference between day and night is also large, so fishing is not allowed. 65438+February 3 1, the temperature difference was 5 degrees the night before, and the sun came out again that day. Yan Diaoyou and other four people went to Dongtianba and found nothing. Liao Diaoyou and other six people were at Tangjiagou Second Weir, and none of them floated.

Third, the influence of water temperature difference on fishing

The temperature of each layer of water is different, which varies with the season and weather (rain or shine, etc.). ). This has a great influence on fish activities. The temperature difference between day and night directly affects the temperature difference of water layer, especially the light plays a decisive role.

From some measured data, the author noticed that the water layer temperature difference has the following characteristics:

(1) In general, the surface water temperature is higher than the bottom water temperature. The surface of water is directly irradiated by sunlight, which makes it easier to heat up. Water is a poor conductor of heat, and the bottom temperature changes slowly. In the past two years, I have only encountered two special situations in which the bottom water temperature is higher than the surface water temperature.

The first time was 19 in February, a snowy day, in Dongtianba, around 10, the temperature was 0.5 degrees, the water meter was 4 degrees and the bottom was 6 degrees. Because the temperature drops rapidly and the specific heat of water is large, it is impossible for the water temperature to drop very low, and the bottom cooling of water is slower, resulting in the special situation that the water temperature is higher than the air temperature and the bottom temperature is higher than the surface temperature of water. The cold wave is coming, and it may be a similar situation. The other time was March 13 10, Huangjiaba, with the temperature of 7 degrees, the water surface of 9 degrees, and the bottom of the water 1 1 degree. In the first two days of this day, the rain weakened. These two times, obviously, the fish were caught more than usual. In another case, the temperature at the bottom of the water is higher than that at the surface of the water, that is, the water freezes. The temperature of the water surface is zero, but the temperature of the bottom of the water is certainly not higher than zero. Ice-breaking fishing is very effective, probably because the water temperature is high.

The measured temperature in Nantong, Jiangsu Province is -5 degrees Celsius, the water surface is 0 degrees, and the water is 1.8 meters and 6 degrees).

⑵ The water layer temperature difference is related to the seasonal climate. In northern Sichuan, the surface temperature of reclaimed water reaches 34 degrees and the lowest is 7 degrees a year. The lowest temperature at the bottom of the water is 6 degrees and the highest is 29 degrees. The maximum temperature difference between surface water and bottom water is 9 degrees, and the minimum temperature difference is 0 degrees (under special circumstances, ice and snow are deficient).

About11-February, the temperature difference between the surface water and the bottom water is small, and even tends to be consistent. Around March-10, the temperature difference is large. During the day, the temperature in the morning is usually lower than the surface temperature of water. When the sun rises, the temperature rises faster than the water temperature, and the water surface rises faster than the bottom. After noon, the temperature is usually higher than the water temperature, and the temperature difference of the water layer increases. The temperature difference of the water layer mainly depends on the time and intensity of sunlight.

Sunny, sunny, water temperature difference changes greatly. This can explain why it is difficult to fish in sunny days in winter or it is still difficult to fish in sunny afternoons. It is reasonable to say that fishing in summer is early, but it is worth analyzing in detail. On August 17, the sun was shining, and almost no fish were caught in Shaxi Tang Yi. At 9: 30, the temperature is 27 degrees, the water meter is 30 degrees and the bottom (2 meters deep) is 27 degrees. At 6 pm, the temperature is 32 degrees, the water meter is 34 degrees, and the bottom is 29 degrees. I expected to get something at sunset, but I didn't catch any fish at night. The reason is that at night, although the temperature drops slightly, the temperature of the water meter remains high (due to the slow heat dissipation of water) and the temperature difference of the water layer is large, which leads to serious hypoxia in the water body and the fish can't open their mouths. It can be seen that in most cases, summer is only suitable for early fishing, not for late fishing. In cloudy or cloudy weather, fishing may be late. Of course, night fishing after 9 pm is another matter.

(3) The temperature difference of the water layer is trapezoidal. The closer to the surface, the greater the change; The closer to the bottom, the smaller the change.

Take a diary fragment as an example to analyze. 4 eyes for 4 days, sunny, room temperature 2 1 degree, relative humidity 75%, outdoor last night 2 1 degree, this morning 14 degree, night temperature difference 7 degrees, indicating that the night is cold. It's sunny today, and there is a big temperature difference in the water layer. At 4 o'clock in the afternoon, the temperature is 27 degrees, the water meter is 24 degrees, underwater is 30 cm 2 1 degree, underwater is 2 meters 17 degrees, and the water meter difference is 7 degrees. Fish floats on the water, but it is difficult to catch. The weir mouth is 4 meters deep and the temperature is basically the same as that of 2 meters deep.

The above example not only shows the influence of temperature difference between day and night and water temperature difference on fishing, but also shows that the temperature of each water layer changes in a trapezoidal shape. Under sunlight, the water surface heats up quickly, but the light penetration is not strong and the thermal conductivity of water is small, so the lower temperature changes little, resulting in higher surface water temperature and greater change, while the lower water temperature changes little. In the above example, the temperature drops by 3 degrees at a distance of 30 cm from the water surface, only by 4 degrees from 30 cm to 1.5 m (depth difference 1.2 m), and the temperature difference from 1.5 m to 4 m (depth difference of 2.5 m) can be ignored. In short, the temperature difference in the water layer is not uniform, but decreases geometrically from top to bottom. In deep water, the temperature changes very little, and it is even difficult to determine what changes there are.

The author once had a wrong view that the bottom of the water is warm in winter and cool in summer, and fish swim to deep water in winter because it is warmer there. By measuring the temperature difference in the water layer, we have to deny the view that "underwater winter is very warm" on days without ice.