How can I texture 2D surface ?

OpenGL OpenGL: Basic Coding
1

Hello, I want to texture my 2D terrain surface.
I have created the ground mesh and surface mesh separately and everything is okay for ground mesh. But I couldn’t texture the surface mesh correctly. Surface was textured linear on x axis but i wanted surface mesh to follow ground curves. For example, at Hill Climb game surfaces are exactly as I want.

Here is how I create my textures and draw my meshes:

private void initializeTextures() {
        groundTexture = new Texture(Gdx.files.internal(Constants.SIMPLE_GROUND_FN));
        groundTexture.setWrap(Texture.TextureWrap.Repeat, Texture.TextureWrap.Repeat);

        surfaceTexture = new Texture(Gdx.files.internal(Constants.SIMPLE_GROUND_SURFACE_FN));
        surfaceTexture.setWrap(Texture.TextureWrap.ClampToEdge, Texture.TextureWrap.Repeat);
        surfaceTexture.setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear);
    }

    public void draw(SpriteBatch batch){

        batch.setShader(shader);
        shapeRenderer.setProjectionMatrix(GameScreen.getCamera().combined);
        shader.begin();
        shader.setUniformMatrix("u_projTrans", GameScreen.getCamera().combined);
        groundTexture.bind(0);
        shader.setUniformi("u_texture", 0);
        groundMesh.render(shader, GL20.GL_TRIANGLES);
        surfaceTexture.bind(0);
        shader.setUniformi("u_texture", 0);
        shader.setUniformMatrix("u_projTrans", GameScreen.getCamera().combined);
        surfaceMesh.render(shader, GL20.GL_TRIANGLES);
        shader.end();

    }

Vertex and fragment shaders:

#ifdef GL_ES
#define LOWP lowp
precision mediump float;
#else
#define LOWP
#endif

varying vec2 v_texCoords;
uniform sampler2D u_texture;

void main() {
  gl_FragColor = texture2D(u_texture, v_texCoords);
}

attribute vec4 a_position;
attribute vec2 a_texCoord0;
uniform mat4 u_projTrans;
varying vec2 v_texCoords;

void main() {         
 v_texCoords = a_texCoord0;
 gl_Position =  u_projTrans * a_position; 
}

I am new about programming games using OpenGL(libGdx) and really need your helps to achieve this problem.